South Branch Wildlife Management Area: Merck Section (Northern part)
Hunterdon County, NJ

The north part of the WMA is located north of the South Branch of the Raritan River, between Rockafellows Hill Road on the west, south of Sheaf Road on the north, west of Lazy Brook Road on the east, and to the river on the south side.

The south part of the WMA is located south of the South Branch of the Raritan River in Voorhees Corner and Higgins Mills,  with Clover Hill Road on the southwest and Plenhert Road on the southeast, to the east of Fieldstone Place, and the river on the north.

Directions to the northern part:

US 78 west to Exit 24 for Route 523 south; drive from green mileage marker 22 to just south of green mileage marker 14 and turn left onto Barley Sheaf Road ( a total distance of around 8.5 miles).  Drive 0.7 of a mile and turn right onto Rockafellows Hill Road.  Drive about 1.2 miles (where the road bends to the left (and then back right).  On the left had side of the road you will see signs saying something like "Wildlife Refuge Area; No Motorized Vehicles."  Park along the road on the left hand side by the woods area. 

(For maps see:

Directions to the southern part:

Merck Property (Undeveloped)
Clover Hill Road, Hillsborough, Raritan and Readington Townships, Hunterdon County, NJ
537 Acres

From the northern part of the conserved land:

Drive south on Rockafellows Hill Road to its intersection with Route 22; cross straight over Route 22 to Dory Dilts Road; at the T-intersection with Route 613 turn right and head south on Route 613 for 0.6 of a mile; turn left onto Clover Hill Road; drive 0.3 of a mile and turn left into the preserve; there is a small parking area on the left of the blocked-off side-road.


Merck sold the property to the state of New Jersey and NJCF for less than fair market value.

NJCF purchased about 115 acres in Raritan Township using funding from the Green Acres Program, and plans to transfer ownership of the land to the Hunterdon County Park System. The State purchased the remainder of the land, approximately 422 acres, which will be managed by the Division of Fish and Wildlife.

The Hunterdon County New Jersey Chamber of Commerce and the Hunterdon Economic Partnership honored Merck with its Public/Private Partnership Award for the acquisition and rezoning of Merck property (Whitehouse West) and Three Bridges Farm sale.


hay fields, disturbed fields, thickets, as well hardwood and softwood forests, open pastureland, forested uplands, and nine acres of frontage on the Raritan River


31 Aug 2000 From: "Jay Biskup"; 537 ACRES OF LAND PRESERVED BY MERCK, THE STATE OF NEW JERSEY AND THE NEW JERSEY CONSERVATION FOUNDATION; New Jersey Conservation Foundation (NJCF)  preserved this land with a unique private-public partnership between the property's owner, Merck & Co., Inc., the State of New Jersey, and NJCF.  Garden State Environews:


Parked on Rockafellow Hill Road. Walked along the hedge by the roadside to find a way in.  Found it (across from house #157) and went in.  The path is a rough one with multiflora rose trying to close it down.  The path took me down to a small stream.  I walked north along the path a little ways to find an easy cross-over.  I quickly got through the woods and came upon a huge field, one of many in the area.  I can tell this is the piedmont region because of the red shale soil.  Headed north on a wide path along the side of the field.  Came to a rough road.  Followed it to the right (east).  Crossed a stream that flows over bare red shale rock.  Headed northeast with a stream on my left and a field on the right.  Came to a fork in the road.  I go right uphill to a huge field.  On the right is a group of abandoned farm buildings.  Across the field I could see a row of houses.

I turn back.  Take a left fork heading right through the middle of a big field.  I reach the end of this particular field and hit a very wet area.  Decide not to get my boots wet, so I turn around and head back to the fork.  Turned right and returned the way I came.  

Drove south along Rockafellow Hill Road and turned left onto River Road.  Drove 0.3 of  a mile to where the road bore to the left.  I parked here because I saw the diamond sign of a Wildlife Management Area.  Searched for a way in.  Found a very narrow path that involved quite a bit of bushwhacking.  The multiflora rose was particularly difficult to get past.  The path becomes overgrown and I bushwhack through the tall grasses and come to a small creek.  Explore another part of the creek  -- a small oxbow.  Turn around and return the way I came.  (If I had jumped the creek and continued south, I would eventually have come to the river itself.)

Near the southern end of Rockafellow Hill Road are railroad tracks followed by a bridge over the river. (The views of the river from the one-lane bridge was quite pleasing.)

Dr. Patrick L. Cooney
* = plant found in bloom on date of field trip, 7/20/04

Acer negundo (ash leaf maple)
Acer rubrum (red maple)
Acer saccharinum (silver maple)
Ailanthus altissima (tree of heaven)
Catalpa sp. (catalpa)
Fraxinus americana (white ash)
Juniperus virginiana (red cedar)
Maclura pomifera (osage orange)
Morus alba (white mulberry)
Pinus strobus (white pine)
Prunus serotina (black cherry)
Quercus rubra (red oak)
Sassafras albidum (sassafras)
Ulmus americana (American elm)

Cornus amomum (swamp dogwood)
Elaeagnus umbellata (autumn olive)
Rhus typhina (staghorn sumac)
Rosa multiflora (multiflora rose) 
Rubus occidentalis (black raspberry)
Rubus phoenicolasius (wineberry)
Rubus sp. (black berry)

Lonicera japonica (Japanese honeysuckle) *
Parthenocissus quinquefolia (Virginia creeper)
Toxicodendron radicans (poison ivy)
Vitis spp. (fox grape)

Achillea millefolium (yarrow) *
Agrimonia sp. (agrimony) *
Alliaria petiolata (garlic mustard) *
Allium vineale (field garlic) *
Ambrosia artemisiifolia (common  ragweed)
Apocynum sp. (dogbane)
Arctium sp. (burdock)
Artemisia vulgaris (common mugwort)
Asparagus officinalis (asparagus)
Barbarea vulgaris (common wintercress)
Carduus acanthoides (plumeless thistle) *
Centaurea jacea (brown knapweed) or the hybrid?
Centaurea maculosa (spotted knapweed) *
Chenopodium album (pigweed)
Chrysanthemum leucanthemum (ox-eye daisy) *
Cichorium intybus (chicory) *
Cirsium arvense (Canada thistle) *
Cirsium vulgaris (bull thistle)
Coronilla varia (crown vetch) *
Daucus carota (Queen Anne's lace) *
Dianthus armeria (Deptford pink) *
Erechtites hieraciifolia (pileweed)
Erigeron annuus (daisy fleabane ) *
Eupatorium perfoliatum (boneset)
Eupatorium rugosum (white snakeroot)
Euthamia graminifolia (grass-leaved goldenrod)
Fragaria sp. (strawberry)
Geum canadense (white avens) *
Gnaphalium obtusifolium (sweet everlasting) *
Hackelia virginiana (Virginia stickseed) *
Hieracium sp. (hawkweed)
Impatiens capensis (orange jewelweed) *
Leonurus cardiaca (motherwort)
Lepidium virginicum (poor man's pepper)
Lespedeza stipulacea (Korean bush clover)
Linaria vulgaris (butter and eggs) *
Lobelia puberula (downy lobelia) *
Lythrum salicaria (purple loosestrife) *
Nepeta cataria (catnip) *
Oxalis sp. (yellow wood sorrel) *
Penstemmon sp. (beardtongue)
Phytolacca americana (pokeweed) *
Pilea pumila (clearweed)
Plantago lanceolata (English plantain) *
Plantago major (common plantain)
Polygonum cespitosum (cespitose knotweed) *
Polygonum sagittatum (arrow-leaved tearthumb)
Potentilla canadensis (dwarf cinquefoil)
Potentilla norvegica (rough cinquefoil) *
Potentilla recta (rough-fruited cinquefoil)
Prunella vulgaris (self-heal) *
Rumex crispus (curled dock)
Rumex obtusifolius (broad leaved dock)
Saponaria officinalis (bouncing bet) *
Solanum carolinense (horse nettle)
Solidago sp. (goldenrod)
Taraxacum officinale (common dandelion) *
Teucrium canadense (American germander) *
Trifolium arvense (rabbit foot clover) *
Trifolium hybridum (alsike clover) *
Trifolium pratense (red clover) *
Trifolium repens (white clover) *
Typha latifolia (broad-leaved cattail)
Urtica dioica var. dioica (stinging nettle) *
Verbascum thapsus (common mullein)
Verbena urticifolia (white vervain) *
Xanthium sp. (clotbur)

Juncus tenuis (path rush)

Dactylis glomerata (orchard grass)
Bromus inermis (smooth brome grass)
Echinochloa sp. (barnyard grass)
Elymus hystrix (bottle brush grass)
Hordeum sp. (barley) ?
Microstegium vimineum (Japanese stilt grass) 
Phleum pratense (Timothy grass)
Phalaris arundinacea (reed canary grass)
Schizachyrium scoparium (little blue stem grass)
Setaria faberi (nodding foxtail grass)