South Branch Wildlife Management Area: Merck Section (southern section)
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:


7/20/04.  Brief stop after visiting two other sites.  I had done fields earlier and was in no mood to do more of them.  Walked along the side of the nature preserve.  I also investigated a little of one of the woods hedges between fields. 

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

Acer platanoides (Norway maple)
Albizia julibrissin (silk tree)
Carya glabra (pignut hickory)
Fraxinus americana (white ash)
Morus alba (white mulberry)
Picea abies (Norway spruce)
Picea pungens var. glauca (blue spruce) planted
Pinus strobus (white pine)
Prunus serotina (black cherry)
Pyrus sp. (crab apple)
Quercus alba (white oak)

Cornus amomum (swamp dogwood)
Elaeagnus umbellata (autumn olive)
Rosa multiflora (multiflora rose) 
Rubus occidentalis (black raspberry)
Rubus phoenicolasius (wineberry)
Rubus sp. (black berry)
Syringa vulgaris (lilac) Pinus strobus (white pine)
Viburnum prunifolium (blackhaw viburnum)

Lonicera japonica (Japanese honeysuckle) *
Parthenocissus quinquefolia (Virginia creeper)
Toxicodendron radicans (poison ivy)

Achillea millefolium (yarrow) *
Alliaria petiolata (garlic mustard) *
Allium vineale (field garlic) *
Ambrosia artemisiifolia (common  ragweed)
Asclepias syriaca (common milkweed)
Cichorium intybus (chicory) *
Cirsium arvense (Canada thistle) *
Cirsium vulgaris (bull thistle)
Commelina communis (Asiatic dayflower)
Daucus carota (Queen Anne's lace) *
Erechtites hieraciifolia (pileweed)
Erigeron annuus (daisy fleabane ) *
Eupatorium rugosum (white snakeroot) *
Euthamia graminifolia (grass-leaved goldenrod)
Geum canadense (white avens) *
Impatiens capensis (orange jewelweed) *
Oxalis sp. (yellow wood sorrel) *
Phytolacca americana (pokeweed) *
Plantago lanceolata (English plantain) *
Polygonum cespitosum (cespitose knotweed) *
Polygonum virginianum (jumpseed)
Rumex obtusifolius (broad leaved dock)
Saponaria officinalis (bouncing bet) *
Solidago juncea (early goldenrod) *soon
Trifolium pratense (red clover) *
Trifolium repens (white clover) *
Verbascum thapsus (common mullein)
Verbena urticifolia (white vervain) *
hollyhock *

Juncus tenuis (path rush)

Dactylis glomerata (orchard grass)
Bromus inermis (smooth brome grass)
Hordeum sp. (barley) ?
Microstegium vimineum (Japanese stilt grass) 
Phragmites australis (giant reed grass)
Setaria faberi (nodding foxtail grass)