Rockland County, NY
556 acres


Iona Island is located in the Town of Stony Point in Rockland County, six miles south of West Point. From NYC go north on the Palisades Parkway about 40 miles toward Bear Mountain Bridge. Take 9W south at the traffic circle, passing Bear Mountain Inn. Iona Marsh is 1 mile south of the Bear Mountain Bridge. Turn left and drive over the railroad tracks and park outside the gate along the railroad.


Iona Island is a mostly Precambrian gneiss bedrock island in the midst of the Hudson Highlands, bordered to the west and the southwest by Salisbury and Ring meadows, two large tidal marshes; and the mouth of Doodletown Bight, an expanse of shallows and mudflats. Doodletown Brook flows into the area.

"The Iona Island Delta, consisting mainly of mud deposited by Doodletown Brook in recent time, occupies the channel followed by the Hudson before the Pleistocene Epoch."  (Wyckoff 1971:78) Sediments are more than 100 feet thick.

The gneiss rock is very resistant to erosion and forms the rocky knobs of Iona that project 100 feet above the river. (see Hudson River NERR website)

Around the island is a 200 acre marsh on the former site of an ancient horseshoe bend. The bend was bypassed with the last glacier that came through the area and straightened out the river channel. (Binnewies, 2001:110-111)


In the 1970s, when there was abundant rainfall, the Hudson ran full and strong, pushing the seawater downstream, so that the river at Iona was only mildly brackish.

This is a brackish -- slightly salty -- river marsh. 50 miles from the ocean, the Hudson is still tidal here. The salinity of the marsh varies significantly, depending on the rainfall upstream.


A separate island, Round Island, was attached to the south end of Iona Island with fill in the early 20th century. Iona Island and its associated tidal wetlands have been designated a National Natural Landmark by the National Park Service.

Native Americans occupied the island as much as 5,500 years ago. Archaeological sites have been scientifically excavated and documented on Iona Island with some of the artifacts on display at the Bear Mountain Trailside Museum and Zoo.

Whites settled on the island in 1683.

1849 -- John Beveridge becomes owner of the island. He sells part-interest in the island to his son-in-law, Dr. C. W. Grant. His attempt to develop an "Iona" variety of grape only resulted in a wine of mediocre taste and his business failed. (Binnewies, 2001:111)

In the Mountain House era, Iona Island was a favorite retreat for day visitors. It had a ferris wheel, carousel and picnic grounds. It also had a resort hotel. (Dunwell 1991:92)

On the 1854 map what became Iona Island was made of two northerly islands (known as Salisbury Island), while the southerly island was known as Round Island.

On the 1859 map the most northerly island was known as Ionia Island, the middle one known as Courtland Island, and the one in the south east was labeled Dr. Grant.

At the time of the Civil War, Iona Island produced commercially grown fruit. During the Civil War itself, the island was converted to a resort hotel.

Later owners turned the island into a resort complete with picnic ground. The famous Irish-American fighter, John L. Sullivan, world heavyweight boxing champion, frequently visited the island. (Binnewies, 2001:111)

On the 1876 map there is a dotted line going across the three islands with the designation "Proposed Chicago & West Shore Railroad."

On the 1891, map there are 4 island-like areas: Iona Island, Depot, unmarked, and another area known with the designation D. E. Donellan.

In 1899, the Navy purchased Iona Island for $160,000 dollars for use as a munitions depot through World War II. The US Navy thought the location of the island, being 40 miles upriver from New York City, provided it protection from attack. Just before US entry into World War I the US Navy established an ammunition depot at Iona Island with enough explosives to supply both the US and British fleets in the Atlantic. (Binnewies, 2001:98-99)

Its construction began around 1900. This, as well as an aqueduct from Doodletown to supply water to the island, provided jobs for the people living in the now abandoned village of Doodletown. There was an explosion at the naval magazine and a man from Doodletown died.

The 1920 maps shows Iona Island with the U.S. Naval Station designation and the West Shore Railroad.

After 1945 the Navy gradually deactivated the Iona Island munitions depot. Scores of decommissioned combat and merchant vessels were mothballed and anchored in the Hudson River off Jones Point. The government used the vessels for surplus grain storage.

In 1965, the Palisades Interstate Park Commission (PIPC) purchased the island for use as a recreation area and bird sanctuary.

Sources: Dunwell, 1991, and Stalter, Elizabeth "Perk." 1996. Doodletown: Hiking Through History in a Vanished Hamlet on the Hudson. Bear Mountain, NY: Palisades Interstate Park Commission Press.

Dr. Robert Zaremba; Dr. Patrick L. Cooney; Dr. William F. Standaert

Acer rubrum (red maple)
Ailanthus altissima (tree-of-heaven)
Aralia spinosa (Hercules' club) 7/26/96 soon
Betula lenta (black birch)
Betula populifolia (gray birch)
Carya glabra (pignut hickory)
Carya ovata* (shagbark hickory)
Carya tomentosa (mockernut hickory)
Celtis occidentalis (northern hackberry)
Chamaecyparis thyoides (Atlantic white cedar -- planted) *
Cornus florida (flowering dogwood)
Fraxinus americana (white ash)
Fraxinus pensylvanica* (red ash)
Ilex opaca (American holly)
Juniperus communis (juniper)
Juniperus virginiana (red cedar)
Magnolia tripetala (umbrella magnolia -- planted) *
Morus alba (white mulberry) *
Nyssa sylvatica (tupelo)
Ostrya virginiana (hop hornbeam)
Paulownia tomentosa (empress tree)
Pinus rigida (pitch pine)
Prunus serotina (black cherry)
Quercus bicolor* (swamp white oak)
Quercus prinus (chestnut oak)
Quercus rubra (red oak)
Quercus velutina (black oak)
Rhus typhina (staghorn sumac)
Salix alba* (white willow)
Salix babylonica (weeping willow)
Salix fragilis (crack willow)
Salix nigra (black willow)
Ulmus americana (American elm)
Ulmus rubra (slippery elm)

Alnus serrulata (smooth alder)
Amorpha fruticosa (false indigo)
Aronia sp. (chokeberry)
Baccharis halimifolia * (groundsel tree)
Berberis thunbergii (Japanese barberry)
Clethra alnifolia* (sweet pepperbush)
Cornus amomum (swamp dogwood)
Ilex verticillata (winterberry holly)
Ligustrum sp. (privet)
Lyonia ligustrina (maleberry)
Mitchella repens (partridgeberry)
Opuntia humifusa (prickly-pear cactus)
Ribes rotundifolium* (Appalachian gooseberry)
Rosa multiflora (multiflora rose)
Rosa palustris (swamp rose)
Rubus phoenicolasius (wineberry)
Salix purpurea (willow)
Toxicodendron vernix* (poison sumac)
Vaccinium corymbosum* (high bush blueberry)
Viburnum prunifolium (blackhaw viburnum)
Zanthoxylum americanum (northern prickly ash)

Ampelopsis brevipedunculata (porcelain berry)
Amphicarpaea bracteata (hog peanut) Celastrus orbiculatus (Asiatic bittersweet)
Calystegia sepium (hedge bindweed) 7/26/96 8/13/95
Clematis terniflora (sweet autumn clematis)
Convolvulus arvensis (field bindweed)
Cuscuta pentagona* (dodder)
Lonicera japonica (Japanese honeysuckle) 7/13/01 7/26/96 8/13/95 11/6/99
Mikania scandens (climbing hempweed)
Parthenocissus quinquefolia (Virginia creeper)
Solanum dulcamara (bittersweet nightshade)
Toxicodendron radicans (poison ivy)
Vincetoxicum nigrum (black swallowwort) 7/13/01 8/13/95
Vitis aestivalus (summer grape)
Vitis labrusca (fox grape)

Acalypha virginica v. rhomboidea (three seeded mercury)
Achillea millefolium var. roseum (yarrow)
Acorus americanus (sweet flag)
Agrostemma githago (corn cockle)
Alisma triviale (northern water plantain)
Alliaria petiolata (garlic mustard)
Allium vineale (field garlic) 8/13/95
Althaea officinalis (holly hock mallow)
Amaranthus cannabinus (salt-marsh water hemp) 8/13/95
Ambrosia artemisiifolia (common ragweed) 8/13/95
Apocynum cannabinum (Indian hemp dogbane)
Aquilegia canadensis (columbine)
Arabis lyrata (lyre-leaved rockcress) 7/13/01 7/26/96
Arenaria michauxii ?
Arenaria serpyllifolia (thyme-leaved sandwort)
Arenaria stricta (rock sandwort)
Arisaema triphyllum (jack-in-the-pulpit)
Artemisia vulgaris (mugwort)
Asclepias incarnata (swamp milkweed) 7/26/96 8/13/95
Asclepias syriaca (common milkweed)
Asclepias verticillata (whorled milkweed)
Asplenium platyneuron (ebony spleenwort)
Aster cordifolius (heart-leaved aster) 11/06/99
Aster lanceolatus var. simplex (panicled aster)
Aster novi-belgii (New York aster)
Aster pilosus var. pringlei (aster) 11/06/99
Aster subulatus (annual salt-marsh aster)
Aster cf. tenuifolius
Atriplex hastata (orache)
Berteroa incana* (hoary alyssum)
Bidens bidentoides (southern estuarine beggar tick)
Bidens eatonii (northeastern estuarine beggar tick)
Bidens hyperborea (northern estuarine beggar tick)
Boehmeria cylindrica (false nettle)7/26/96 8/13/95
Callitriche sp. (water starwort)
Campanula rotundifolia (harebell) 7/13/01 7/26/96
Cardamine sp.
Centaurea maculosa (spotted knapweed) 7/26./96 8/13/95 11/06/99
Cerastium vulgatum (mouse-ear chickweed)
Ceratophyllum demersum (coontail)
Chaenorrhinum minus (dwarf snapdragon) 7/13/01 7/26/96
Chelidonium majus (celandine)
Chelone glabra (white turtlehead)
Chenopodium album (pigweed)
Chenopodium botrys (Jerusalem oak goosefoot)
Chrysanthemum leucanthemum (ox-eye daisy) 8/13/95
Cichorium intybus (chicory) 7/13/01 8/13/95 11/06/99
Cirsium arvense (Canada thistle) 7/26/96 8/13/95
Cirsium vulgare (bull thistle) 8/13/95
Conyza canadensis (horseweed) 8/13/95
Crassula aquatica (pygmy-weed)
Daucus carota (Queen Anne's lace) 7/26/96 8/13/95 11/06/99
Dianthus armeria (Deptford pink) 7/13/01 7/26/96 8/13/95
Echium vulgare (viper's bugloss) 7/13/01 7/26/96 8/13/95 11/06/99
Elatine minima (waterwort)
Elodea canadensis (common waterweed)
Elodea nuttallii (free-flowered waterweed)
Erechtites hieraciifolia (pilewort) 8/13/95
Erigeron annuus (daisy fleabane) 7/26/96 8/13/95
Eupatorium perfoliatum (boneset) 8/13/95
Eupatorium serotinum* (late-flowering boneset)
Euphorbia cyparissias* (cypress spurge)
Euphorbia esula (leafy spurge) 7/13/01
Euphorbia maculata (milk purslane)
Euphorbia nutans* (eyebane spurge)
Galium sp. (bedstraw)
Gnaphalium obtusifolium (sweet everlasting) 8/13/95
Habenaria clavellata (club-spur orchid)
Hedeoma pulegioides (American pennyroyal)
Helenium autumnale (sneezeweed) 8/13/95
Helianthus divaricatus (woodland sunflower) 7/13/01
Helianthus strumosus (pale-leaved sunflower)
Hibiscus moscheutos (swamp rose mallow) 7/26/96 8/13/95
Hypericum gentianoides (orange grass St. Johnswort)
Hypericum perforatum (common St. Johnswort) 7/13/01 7/26/96 8/13/95
Hypoxis hirsuta (yellow star grass) 7/13/01
Impatiens capensis (orange touch-me-not) 7/26/96 8/13/95
Iris pseudacorus (larger blue flag)
Krigia virginica (dwarf dandelion) 11/06/99
Lechea racemulosa (pinweed)
Lemna minor (lesser duckweed)
Lepidium virginicum (poor man's pepper) 7/26/96 8/13/95
Limosella aquatica* (northern mudwort)
Limosella australis ?
Linaria canadensis* (blue toadflax)
Linaria vulgaris (butter-and-eggs) 7/13/01 7/26/96 8/13/95 11/06/99
Linum sp. (flax)
Liparis loeselii (Loesel's twayblade)
Lobelia cardinalis (cardinal flower) 8/13/95
Lotus corniculatus (birdfoot trefoil) 7/13/01 7/26/96 8/13/95
Ludwigia palustris (marsh purslane)
Lycopus sp. (bugleweed)
Lythrum salicaria (purple loosestrife) 7/26/96 8/13/95
Medicago lupulina (black medick) 7/13/01 7/26/96
Melilotus alba (white sweet clover) 7/13/01 7/26/96 8/13/95
Melilotus officinalis (yellow sweet clover) 7/26/96 8/13/95
Mirabilis nyctaginea (wild four o'clock)
Myosotis sp. (forget-me-not)
Myriophyllum spicatum (Eurasian watermilfoil)
Najas flexilis (northern waternymph)
Najas marina (alkaline water nymph)
Nepeta cataria (catnip) 7/13/01 8/13/95
Nuphar luteum ?
Oenothera biennis (common evening primrose) 7/26/96
Peltandra virginica (arrow arum)
Physalis heterophylla* (clammy ground cherry)
Pilea pumila (clearweed)
Plantago lanceolata (English plantain) 7/13/01 7/26/96 8/13/95
Platanus occidentalis (American sycamore)
Pluchea odorata (salt-marsh fleabane) 8/13/95
Polygala verticillata (whorled milkwort) 7/13/01 7/26/96
Polygonum arenastrum (common knotweed) 11/06/99
Polygonum cespitosum (cespitose smartweed) 7/13/01
Polygonum hydropiperoides (mild water pepper) 8/13/95
Polygonum punctatum (dotted smartweed) 7/26/96
Polygonum sagittatum (arrow-leaved tearthumb)
Polygonum tenue (slender knotweed)
Pontederia cordata (pickerelweed) 7/26/96 8/13/95
Potamogeton crispus (curly pondweed)
Potamogeton richardsonii (Richardson's pond weed)
Potentilla argentea (silvery cinquefoil) 7/ 19/01
Potentilla norvegica (rough cinquefoil) 7/13/01
Prunella vulgaris (self-heal) 7/13/01
Pycnanthemum incanum (hoary mountain mint) 7/13/01
Pycnanthemum virginianum (Virginia mountain mint) 7/13/01
Ranunculus sp. (buttercup)
Rudbeckia hirta var. pulcherrima (black eyed Susan) 7/13/01
Rumex crispus (curled dock)
Rumex sp. (dock)
Sabatia dodecandra (twelve-stemmed marsh pink)
Sagina japonica* (Japanese pearlwort)
Sagina procumbens* (pearlwort)
Sagittaria calycina var. spongiosa (Mississippi arrowhead)
Sagittaria latifolia (broad-leaved arrowhead)
Sagittaria rigida (sessile-fruited arrowhead)
Sagittaria subulata (Hudson River arrowhead )
Samolus floribundus (water pimpernel)
Samolus valerandii ssp. parviflorus ?
Saponaria officinalis (bouncing bet) 8/13/95
Scutellaria galericulata (marsh skullcap) 8/13/95
Sedum sarmentosum* (sedum)
Selaginella rupestris* (rock spikemoss)
Silene vulgaris (bladder campion) 7/13/01 7/26/96 8/13/95
Sium suave (water parsnip) 7/13/01 7/26/96
Smilax rotundifolia (common greenbrier)
Solanum carolinense (horse nettle)
Solidago bicolor (silverrod)
Solidago nemoralis (gray goldenrod)
Solidago rugosa (rough-stemmed goldenrod)
Solidago uliginosa (northern bog goldenrod)
Sonchus sp. (sow thistle)
Spirodela polyrhiza (spirodela)
Strophostyles helvula (trailing wild bean)
Symplocarpus foetidus (swamp cabbage)
Taraxacum officinale (dandelion) 7/26/96
Teucrium canadense (American germander) 7/26/96 8/13/95
Thalictrum pubescens (tall meadowrue)
Trapa natans (water chestnut)
Trichostema dichotomum (blue curls) 8/13/95
Typha angustifolia (narrow-leaved cattail)
Typha latifolia (broad-leaved cattail)
Urtica dioica var. procera (tall stinging nettle)
Vallisneria americana (water celery)
Verbascum blattaria (moth mullein) 7/13/01 8/13/95
Verbascum thapsus (common mullein) 7/13/01 8/13/95
Verbena bracteata (prostrate vervain) 7/13/01
Verbena hastata (blue vervain) 7/26/96
Verbena simplex (narrow-leaved vervain)
Verbena stricta* (hoary vervain)
Verbena urticifolia (white vervain) 7/26/96 8/13/95
Veronica officinalis (common speedwell)
Vicia sp. (cracca?) (vetch)
Viola sp. (violet)
Zannichellia palustris (horned pondweed)

Rushes and Sedges:
Bulbostylis capillaris
Carex bushii (Bush's sack sedge)
Carex comosa (bearded sack sedge)
Carex complanata (flattened sedge) 7/13/01
Carex crinita* (long-haired sack sedge)
Carex cristatella* (small-crested sack sedge)
Carex granularis (granular sack sedge)
Carex lurida (sedge)
Carex stricta (tussock sack sedge)
Carex vulpinoidea (fox-like sack sedge)
Cyperus filicinus* (fern-like flatsedge)
Cyperus flavescens v. poaeformis (yellow nutsedge)
Cyperus odoratus* (fragrant nutsedge)
Cyperus strigosus (umbrella nut sedge)
Eleocharis parvula (spike rush)
Juncus tenuis (path rush)
Scirpus americanus (Olney three-square bulrush)
Scirpus cylindricus
Scirpus fluviatalis (river bulrush)

Agrostis gigantea (red-top grass)
Agrostis perennans (autumn bentgrass)
Aira caryophyllea (silver hairgrass)
Bromus inermis* (smooth brome grass)
Bromus japonicus* (Japanese brome grass)
Calamagrostis cinnoides
Calamagrostis epigejos* (feathertop grass)
Dactylis glomerata (orchard grass)
Danthonia spicata (poverty oatgrass)
Deschampsia flexuosa (hairgrass)
Digitaria sanguinalis (hairy crab grass)
Echinochloa sp. (barnyard grass)
Echinochloa walteri (salt-marsh cockspur)
Eleusine indica (goose grass)
Elymus hystrix (bottlebrush grass)
Elymus riparius (streambank wild rye grass)
Elymus virginicus (wild rye grass)
Eragrostis pectinacea (stink grass)
Eragrostis spectabilis (purple love grass)
Festuca ovina (sheep fescue grass)
Leersia oryzoides (rice cutgrass)
Leptoloma cognatum (fall witch grass)
Microstegium vimineum (Japanese stilt grass)
Muhlenbergia sp. (muhly grass)
Oryzopsis racemosa (blackseed oatgrass)
Panicum clandestinum (deer-tongue grass)
Panicum depauperatum (panic grass)
Panicum virgatum (switch grass)
Phalaris arundinacea (canary reed grass)
Phleum pratense (timothy grass)
Phragmites australis (giant reed grass)
Poa compressa (Canada bluegrass)
Poa pratensis (Kentucky bluegrass)
Schizachyrium scoparium (little blue stem grass)
Setaria faberi (nodding foxtail grass) 7/26/96
Setaria glauca (yellow foxtail grass) 7/26/96
Setaria viridis (green foxtail grass) 7/26/96
Spartina cynosuroides (big cordgrass)
Spartina pectinata (prairie cordgrass)
Tridens flavus (purple top grass)
Tripsacum dactyloides (gama grass)
Triticum aestivum* (wheat)
Zizania aquatica (wild rice)

Ferns and Fern Allies:
Asplenium rhizophyllum (walking fern)
Asplenium trichomanes (maidenhair spleenwort)
Cheilanthes lanosa (woolly lip fern)
Dennstaedtia punctilobula (hay-scented fern)
Dryopteris marginalis (marginal woodfern)
Onoclea sensibilis (sensitive fern)
Osmunda regalis (royal fern)
Polypodium virginianum (rock cap fern)
Thelypteris palustris (marsh fern)

* Gordon C. Tucker and Jack Froct, July 31, 1993.
7/13/01 with Linda Kelly

IONA ISLAND, NY, July 10, 1955.

Exploration of the fresh water swamp on this island was not attempted because of the excessive heat. Yet, on the swamp edge and on the knoll, a number of interesting plants were seen, at what the leader believes is their only station in the county. They were Cheilanthes lanosa, Arisaema stewardsonii, Habenaria clavellata, Zanthoxylum americanum, Ptelea trifoliata, Asclepias verticillata, and Campanula rotundifolia forma albiflora. Attendance: Torrey 8, Rockland Audubon, 6 Leader, J. Harry Lehr.

June 16, 1957.

One of the botanical features of this area is a single specimen of Ptelea trifoliata (common hoptree), the only one known in Rockland County. This field trip disclosed the tree all but dead as the result of right-of-way spraying by the railroad where this plant grew beside the tracks. Yet, this loss was somewhat compensated by the discovery of a station on the island for Arenaria stricta (rock sandwort), a rarity within the Torrey range and a new addition to the flora of Rockland County. Attendance, Torrey 5; Connecticut Botanical Society 1. Leader, J. Harry Lehr.

June 5 1960

Although both Typha angustifolia and T glauca were far enough advanced in bud for their difference to be noted, the station for Arisaema stewardsonii was disappointing. Scores of plants were observed yet none were or had been in bloom. Could an abnormally high water table in the area in May have been responsible for this total lack of bloom?

On the shore of the inlet at the north end of the island Amorpha fruticosa was found in flower. Along the railroad tracks which bisect the island, two additions were made to the list of Rockland County plants which is a continuing study of the leader. They were Agrostemma githago (corn cockle), a single specimen, and Mirabilis nyctaginea (umbrellawort), a western plant rapidly becoming naturalized in the east. But the railroad tracks also produced a disappointment, for the single specimen of Ptelea trifoliata reported from Rockland County is now a dead skeleton. The leader first found this tree in 1953 and its history since then has been one of yearly deterioration. The reason? Indiscriminate right-of-way spraying by the railroad. Attendance 4. Leader J. Harry Lehr.

8/20/63. The island contains at least 40 species unknown elsewhere in the county, and a number of rarities or plants at the northernmost or southernmost known limits of their range in New York State. Some of them are

Apocynum sibiricum and its prostrate form arenarium
Arenaria stricta
Campanula rotundifolia
Cheilanthes vestita
Cyperus flavescens var poaeformis
Elodea nuttallii
Habenaria clavellata
Lechea racemulosa
Lespedeza virginica
Liparis loeselii
Mirabilis nyctaginea
Solidago uliginosa
Solidago sempervirens
Tripsacum dactyloides
Typha glauca
Viburnum dentatum
Vitis riparia

Most of these were seen on this foray and the leader added Lespedeza virginica to his growing list of Rockland County plants. Trip leader, J. Harry Lehr. Attendance 17.

June 20, 1966 p. 141
J. Harry Lehr

September 11, 1983.

We visited this extensive Hudson River marsh at high tide but still managed to find a diverse assemblage of species. The emergent wetland is dominated by Typha angustifolia and Phragmites australis but also includes Zizania aquatica, Lythrum salicaria, Bidens eatonii, Scirpus cylindricus, Echinochloa walteri, Amaranthus cannabinus, Sium suave, Typha latifolia, Pontederia cordata, Peltandra virginica, Aster subulatus, Pluchea odorata, Sagittaria calycinia, Sagittaria latifolia, Leersia oryzoides, and Hibiscus moscheutos.

Fragments of submerged flora washed along the edge of the marsh included Ceratophyllum demursum, Myriophyllum spicatum, Najas flexilis, Potamogeton crispus, and Vallisneria americana.

We found a few plants of Trapa natans which apparently is reaching its downstream limit in the Hudson River. Lemna minor and Spirodela polyrhiza were floating on the water surface. A return trip at low tide should reveal additional species that grow lower in the intertidal zone.

Leaders, Alfred E. Schuyler and Naomi Dicker.