Princeton Township, Mercer County, NJ
77 acres  


From Nassau Street in downtown Princeton take NJ 2-6 north for less than one mile to Mountain Avenue.  Turn left on Mountain Avenue and follow for a short distance to parking area for North Side Community Park on the right.  Mountain Lakes is adjacent to the west side of this park.

Mountain Lakes Nature Preserve, Mountain Avenue, off Route 206 North. 609-683-9022. Self-guided nature walks and programs for all ages given by the Friends of Princeton Open Space. Formerly the estate of Edgar Palmer (as in Palmer Square). Bathrooms are in the adjacent Community Park.


There is a valley here with particularly steep slopes on the western and northern sides of the lakes. Soils are finely grained siltstone and shale rock. The property has four streams.


Originally part of William Penn's land grant from King George III.  First owner was Joseph Stockton, relative of Richard Stockton, who signed the Declaration of  Independence.  

18th century --  the land was farmed.  

19th century  --   The Margerum family cut ice from the lakes in the winter and stored it to deliver it to Princeton kitchens in warm weather.

1930  -- the ice company closed and the property not used extensively for some 20 years or so.

1950's --  the present house was constructed.

early 1980's --  the land was put up for sale to developers.

1986  --  this tract was saved from development by the combined efforts of the Nature Conservancy, the Friends of Princeton Open Space, Princeton Township, and the New Jersey Green Acres Program.  Funds for the purchase of the site were provided by a gift from the Willard T. C. Johnson Foundation.  The Nature Conservancy holds a deed on the property which ensures that it will be kept in its natural state.  

1987  --  Mountain Lakes House, owned by Princeton Township, is maintained and operated by the Friends of Princeton Open Space. Revenues from renting the house for weddings and other events support open-space purchases and house maintenance.

May 2001 --  negotiations were completed to preserve the 165 acre Coventry Farm on the Great Road as permanent open space. 28 acres on the east side of the Great Road, directly north of the existing Mountain Lakes municipal park, will be added to the Mountain Lakes park to form a greenway. (

The Greater Mountain Lakes Open Space Area (315 acres) has been called the "central park" of Princeton.  It consists of three sections: Mountain Lakes Preserve and Mountain Lakes North; John Witherspoon Woods; and Community Park North.


Mountain Lakes is a thickly forested valley of mixed oak woods.  It has four streams and three lakes, wetlands, and steep slopes.  There are two rare sedges here, Carex conoidea (field sedge) and Carex frankii (Frank's sedge).  This is a valley.


James Sayen Trail is a 0.9 mile loop around two lakes separated by an old dam.  (see:

It is a short walk to the lake.  Along the way you go through an area dominated by black walnut (Juglans nigra).  The lake does not have as many interesting water plants because the embankments around the lake are too steep -- no room available for marshy or wet meadow plants.  

There is an environmental center at the north end of the lake near the dam.  

map at:

Dr. Patrick L. Cooney

Acer negundo (box elder maple)
Acer platanoides (Norway maple)
Acer rubrum (red maple)
Acer saccharinum (silver maple)
Carya tomentosa (mockernut hickory)
Catalpa sp. (catalpa)
Cornus florida (flowering dogwood)
Fagus grandifolia (American beech)
Fraxinus americana (white ash)
Juglans nigra (black walnut) -- black walnut forest here in certain areas
Juniperus virginiana (red cedar)
Liriodendron tulipifera (tulip tree)
Pinus resinosa (red pine) plantation near abandoned tennis courts
Platanus occidentalis (American sycamore)
Pyrus malus (apple)
Quercus palustris (pin oak)
Quercus rubra (red oak) -- "seven sister" cluster of red oaks in the fence row on the northern boundary
Quercus velutina (black oak)
Robinia pseudoacacia (black locust)
Sassafras albidum (sassafras)
Tsuga canadensis (eastern hemlock) hemlock grove
Ulmus americana (American elm)
Ulmus rubra (slippery elm)

Berberis thunbergii (Japanese barberry)
Ligustrum sp. (privet)
Lindera benzoin (spice bush)
Lonicera morrowii (Morrow's honeysuckle)
Photinia villosa (Oriental photinia) ? this horticultural plant is very common especially along the park road
Rosa multiflora (multiflora rose)
Rubus occidentalis (black raspberry)
Rubus phoenicolasius (wineberry raspberry)
Spiraea sp. (horticultural spiraea)

Celastrus orbiculatus (Asiatic bittersweet)
Lonicera japonica (Japanese honeysuckle)
Solanum dulcamara (bittersweet nightshade) 8/01/98
Toxicodendron radicans (poison ivy)
Vitis riparia (riverbank grape)

Agrimonia sp. (agrimony) 8/01/98
Arisaema triphyllum (Jack-in-the-pulpit)
Bidens connata (beggar tick)
Boehmeria cylindrica (false nettle) 8/01/98
Cirsium arvense (Canada thistle)
Cirsium discolor (field thistle)
Cirsium vulgare (bull thistle) 8/01/98
Claytonia virginica (spring beauty)
Erigeron annuus (common daisy fleabane)
Geum sp. (avens, white or rough)
Impatiens sp. (jewelweed)
Iris sp. (iris)
Lemna sp. (duckweed)
Lobelia inflata (Indian tobacco lobelia) 8/01/98
Ludwigia palustris (marsh purslane)
Mentha arvensis (wild mint) 8/01/98
Polygonum virginianum (jumpseed knotweed) 8/01/98
Ranunculus spp. (buttercup)
Symplocarpus foetidus (skunk cabbage)
Verbascum thapsus (common mullein)
Veronica serpyllifolia (thyme-leaved speedwell)
Xanthium strumarium? (clotbur?)

Rushes and Sedges:
Cyperus sp. (nut or umbrella sedge)
Juncus tenuis (path rush)

Microstegium vimineum (Japanese stilt grass)
Setaria sp. (foxtail grass)