Places We Protect

Mashomack Preserve

New York

A rocky shore looking out onto Gardiners Bay.
Mashomack Preserve Mashomack Preserve in New York © Harold E. Malde

This preserve has 11 miles of coastline and acres of creeks, woodlands and fields.



See what's happening at Mashomack! You can:

Please note that Mashomack's in-person events have been postponed until further notice.

Edged in white by 11 miles of coastline, Mashomack Preserve on Shelter Island is considered one of the richest habitats in the Northeast. Just 90 miles from New York City, the preserve covers a third of the island with 2,039 acres of interlacing tidal creeks, mature oak woodlands, fields, and freshwater marshes.

While many only think of Mashomack Preserve as the "other" side of Shelter Island, the human and natural history of this New York treasure reaches far back into the seventeenth century. Few know that the preserve was once a hunt and game club, and even fewer know that it was nearly transformed into housing developments more than once.  Thankfully, The Nature Conservancy, together with the residents of Shelter Island and Long Island, was able to pull together a last-minute effort to save this "Jewel of the Peconic."

A Brief History of Mashomack Preserve

Shelter Island was originally inhabited by the Manhansets, Native Americans who were part of the wide-spread Algonquin culture.  In 1653 Chief Pogatticut, sachem or "chief", of the Manhansets, deeded all of Shelter Island to Nathaniel Sylvester.  Sylvester, a sugar merchant from Barbados, established a Quaker refuge on the island.

In 1693, Giles Sylvester, Nathaniel's son, sold Mashomack to William Nicoll I, starting a 230-year "reign" of the Nicoll family at Mashomack.  The Nicolls were early settlers in the Islip area.  What is now known as Mashomack was originally called Sachem's Neck (the main body of the preserve) and Mashomack referred only to Mashomack Point.; Mashomack means "where they go by water" and the point was probably an island before a narrow neck formed, connecting it to the rest of the peninsula.

William Nicoll II was the first full-time resident of Mashomack.  William II deeded Mashomack to William III who farmed the land with his family.  Over the years the property was divided among members of the Nicoll family.  Turn-of-the-century notable Nicolls include "Miss Annie" Nicoll, who farmed the still-open fields in the center of the preserve. Dr. Sam Nicoll, her brother, built the Bass Creek Cottage now known as the Manor House.

By 1908, nonresident Nicoll heirs had begun selling their portions of Mashomack.  F.M. Smith (of 20 Mule Borax fame) was one of the buyers and may have built the building now used as the Visitor Center.

In 1925 Otto Kahn, a wealthy German financier, bought Nicoll family holdings and other portions that had been previously sold, reestablishing the integrity of the tract for a real estate investment.  Fortunately, due to the Stock Market Crash of 1929, his development scheme never materialized.

In 1934, the Gerard real estate combine purchased Mashomack from Kahn's estate. The property was leased to several fish and game clubs.  Of the hunt clubs which have used the Mashomack property over the years, the most well remembered is the Mashomack Fish and Game Club.  Most members were wealthy Long Island or New York City folks who joined the Club to hunt pheasant, duck, or deer.  An occasional fox hunt, complete with hounds and horses was also held.  The two fields in the center of the preserve were converted into a skeet range and tennis court.  The well-appointed Manor House served as the Lodge, with delicious French cuisine prepared for the members.  During the Club's residence, a scheme emerged to develop Mashomack into an exclusive housing area.  A golf course, marina, and beautiful waterfront homes were planned, and investors for the project were secured.  Luckily, the development scheme folded in 1979.

It was at this point, after years of patient waiting and careful planning that The Nature Conservancy (TNC) stepped in and was able to secure Mashomack.  Since the 1950's, the Conservancy had expressed hopes of preserving Mashomack because of its population of the then state endangered osprey and rare plants.  The Gerard family (Aeon Realty) and The Nature Conservancy came to an agreement in 1979.  In order to protect Mashomack, the Conservancy would have to buy all assets of Aeon Realty at a purchase price of $10.6 million.

The assets included:

  • 6 Brownstone Houses in New York, NY
  • 2 Warehouses in Miami, FL
  • Oil & Gas Fields from Louisiana to West Virginia
  • Mashomack, 2039 acres on Shelter Island, NY

The Gerards allowed The Nature Conservancy to get contracts of sale on the first three assets which sold for $5.5 million.  The Conservancy then mounted largest fundraising effort in its history to purchase Mashomack.

On January 14, 1980, The Nature Conservancy took title to Mashomack with the support of 1700 Shelter Islanders and Nature Conservancy members, foundations, and corporations nationwide.

For more details on Mashomack's history, see Muriel Porter Weaver's book, Where They Go By Water, available in the Manor House library.



Mashomack has updated trail hours for March 2021, available under the "Visit" tab.


2,039 acres

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Update as of March 2021: Please note that Mashomack has updated trail hours for March 2021. The Preserve will be open from 8 a.m. — 6 p.m., closed Tuesdays. The Visitor Center and restrooms are temporarily closed. The Preserve will be closed from March 22 — April 4 for spring maintenance work. During or following severe weather we may need to close unexpectedly. If the gate is closed, please note that the Preserve is closed. Please do not enter the grounds.

Before you visit, download a trail map to view the available trails that are open to explore.

Please note: No pets allowed.

A birder and botanist's paradise alike, there's no doubt that the biological diversity on Mashomack Preserve is stunning.  Its combination of interlacing tidal creeks, woodlands, fields and coastline make it a superb wildlife habitat for many rare and endangered species.

The extensive salt marshes of Mashomack provide breeding grounds and nursery habitat for the smallest links in the marine chain of life.  The Pine Swamp complex at the western edge of the preserve has been designated a freshwater wetland of unique local importance.  Fourteen hundred acres of upland oak and beech forest are now being allowed to develop into an old-growth forest, a habitat scarce in the Northeast.  Open, grassy meadows provide the sunnier conditions preferred by some wildflowers and birds.  All of these areas are protected and managed to provide a safe haven for native species.

Visitor Center

The Harman Hawkins Visitor Center at Mashomack Preserve was updated in 2004 to provide universal access to all public spaces. The main entrance features direct access from the parking area trail to the front porch. The relatively open space floor plan includes ~36” doorways and displays are built for comfortable viewing from wheelchairs. The two public toilets are both accessible (wide doors, large area for wheelchairs, comfort height commodes and grab bars). An ADA compliant ramp leads from the front porch to the patio and trail head area. The Education Building is also accessible via a ramp.


The Boardwalk at the entrance of Mashomack Preserve is fully compliant with the forest service recommendations and standards for accessibility.

Joan C. Coles Trail

First opened in 2000, The Joan C. Coles Memorial Trail (1 mile in-and-out) is a barrier-free trail that provides scenic views of the preserve’s stunning natural features, amenable to wheelchairs and strollers. 

Manor House

Mashomack Preserve’s Manor House is used as a conference facility and for local community gatherings. It is fully accessible with an exterior ramp for entering and exiting, an accessible restroom and an elevator to the second floor to an accessible bedroom and bathroom.

What to See: Birds

Since 1980, over 200 species of birds, including 79 nesting species, have been recorded at Mashomack Preserve.  No matter what season or time of day you decide to visit, you’re sure to witness something amazing.

In the summer, look for towhees in the understory, scarlet tanagers and Baltimore orioles in the canopy, and red-tailed hawks along the edges of open, grassy meadows.  In the fall, Mashomack serves as a popular migration stopover point for many birds. Black duck, Canada geese, hooded mergansers and other waterfowl winter in our salt marshes and surrounding bays.

Together with nearby Gardiners Island, Mashomack also supports one of the East Coast's largest concentrations of nesting osprey.  The coastal areas and salt marshes are great places to view other birds as well, such as great blue herons, great and snowy egrets, green herons and black-crowned night herons.

What to See: Animals

Mashomack’s many habitats harbor a plethora of animal life. Painted turtles basking on a sunny log or spring peepers chirping their amorous intentions may be found in the freshwater wetlands, along with a shy muskrat. A summer’s day is alive with the sights and sounds of insects: monarch and swallowtail butterflies, dazzling dragonflies, or buzzing cicadas. The common grey squirrel and cheeky chipmunk are almost always sighted, while occasional reports of a black racer or other harmless snakes also surface.

Salt marshes shelter a multitude of marine species including clams, blue claw crabs, and a variety of fishes. The night brings little brown bats and moths, including the beautiful luna and rare Imperial. Other nocturnal creatures may leave footprints, scat, or rubbings to signal that a fox, raccoon, or deer passed by.

What to See: Plants

The only natural community of its kind on Long Island, the Pine Swamp Complex is comprised of plants rooted in a floating mat of sphagnum moss. Probes have found organic accumulations ten feet thick dated to be 3,900 years old. Fringed by water willows and a diverse shrub layer including swamp azalea, highbush blueberry, white alder, winterberry and mountain holly, the swamp also includes a stand of white pines that shelter two state-protected orchids-the whorled pogonia and the pink lady slipper. The Usnea lichen grows on shrubs and trees here, attracting ruby-throated hummingbirds, which use the lichen in their nests.

In accordance with the Department of Justice’s amended regulation implementing Title III of the 1990 Americans with Disabilities Act (ADA) regarding "Other Power‐Driven Mobility Devices,” Mashomack Preserve has completed an assessment of our public areas and trails. While some types of OPDMDs can be accommodated, there are necessary restrictions on their use.