The Mianus River Park

Mianus River Park is a 391 acre nature reserve on the Greenwich / Stamford border in Connecticut. The park, one of a series of green areas in the Mianus River Watershed, features a two mile stretch of the beautiful Mianus River, forest lands, vernal pools, glacial outcroppings, varied wildlife and miles of rolling trails.

Three contiguous properties make up the park:

Mianus River and Natural Park, 110 acres, owned by the Town of Greenwich

Mianus River Park, 187 acres, owned by the City of Stamford

Mianus River State Park, also known as Treetops, 94 acres, owned by the State of Connecticut

The Mianus River begins in a series of ponds located in North Castle, NY. It starts its 20-mile journey to Long Island Sound by flowing northeast into Bedford, NY. From there, the river takes an abrupt turn south flowing through Mianus River Gorge Preserve and into Stamford.

Between Westover Road and Valley Road, the river turns southwest into Greenwich, where it flows through Mianus Pond, over a dam near Rt. 1 into Cos Cob Harbor and, finally into Long Island Sound.

The river is a source of drinking water for over 100,000 residents in lower Greenwich, Stamford and adjoining New York communities, making its protection a key factor in management of the surrounding lands. One of the two public water supply intakes is located downstream of Mianus River Park. Therefore, it is particularly important to find, and maintain a responsible balance between recreation and preservation for users of the Park. The river, its tributaries, and the wetlands, woods and fields of its watershed, provide habitat to support diverse and abundant wildlife, as well as idyllic settings for recreational and cultural activities that respect the delicate balance of nature on these lands.

For more information about the Mianus River Watershed including protection efforts go to mianus.org.

White tailed Deer, Great Blue Heron, Box Turtle

Flora and Fauna

The Mianus River Park features the simple and unadorned natural beauty of ridges and valleys left behind by glacial movement thousands of years ago. Intermittent streams and perched Red Maple swamps are scattered throughout.. A network of trails passes through Oak and Tulip dominated uplands, areas with young Ash and Cherry trees, old stands of Hemlock and Beech trees, an old field, rock outcrops and Mountain Laurel patches. Among the Black Birch, Tulip Tree, Red Ash and Tupelo can be found many types of fern including: Ladyfern, Sensitive Fern, Cinnamon Fern, Maidenhair, Royal Fern and Bracken.

The park’s wetlands are prime breeding pools for many types of salamanders and frogs. The variety of vegetation provides resting and nesting habitats for wildlife, such as ruffed grouse, pheasant, mallards, cranes, heron, songbirds, woodpeckers, squirrels, deer, raccoons, fox, coyote, weasels, mink and river otter, and other small mammals.

The park’s forest is made up of hardwoods such as maples, elms, oaks, tulips, ashes, hickories, cherries, birches, sassafras, tupelos, hackberries, and beeches. Conifers include hemlock and white pines. Squirrels, raccoons, possums, screech owls, tree swallows, and woodpeckers nest in holes in standing dead trees ("snags"). Hawks like the tops of tall trees; robins prefer the lower branches; owls often choose conifers.

Where the understory is undisturbed, the shrub layer is equally diverse, including sweet peppers (Clethra), spicebushes, winterberries, witchhazels, shads (serviceberries), mountain laurels, maple-leaf viburnums, arrowwood viburnums, blueberries, and tree saplings. Many songbirds nest in the shrub layer.

At ground level, there are ferns, grasses, toadstools, and wildflowers. Grouse, thrashers and rabbits nest under the shrubs; foxes, skunks, and tiny rodents dig burrows. Box turtles bury their eggs in loose soil. Chipmunks and snakes often make their homes in the old stone walls.

Along the water, look for cottonwoods, willows and sycamores; shrubs include elderberries, alders, and silky dogwoods. Blue herons and Baltimore orioles often nest in tall trees near water. Weasels, minks, and muskrats burrow in the riverbank. Mallards nest and painted and snapping turtles bury eggs along the riverbank. Salamanders, toads, and frogs lay eggs in the wetland pools. Fish eggs, fingerling fish, and crayfish are found in the nooks and crannies of the riverbed.

Over 150 resident and migratory birds have been spotted in Mianus River Park and around 70 are recorded as breeding in the park. The Friends group has worked with the Audubon Society to create an "Urban Oasis" in the park, with native, bird friendly plants, to provide a resting place for the many birds which migrate through this area.

Around 15 different mammals have been recorded in the park, ranging from white tailed deer to white-footed mice. Many are shy and can most easily be seen early in the morning or later in the day, especially away from the busiest sections of the park.

Of the amphibians, several types of frog and toad have been recorded in the park, namely; the Gray Tree Frog, Pickerel Frog, Wood Frog, American Bullfrog, Spring Peeper, and American Toad. Spotted Salamanders, Red-backed Salamanders, and Eastern Newts are also park residents.

A wonderful resource for further research and printable lists of birds and animals in the area can be found at Audubon Greenwich.


Mianus River Park, like the rest of New England, owes it rocky landscape and other characteristic features to the last of the powerful glacial ice sheets that crushed and carved out Connecticut, leaving its indelible mark on the face of our land today.

The two-mile thick North American Laurentide Ice Sheet covered hundreds of thousands of square miles throughout the majority of Canada and northern United States. The maximum extent of glaciation was approximately 22,000 years ago and created much of the surface geology of southern Canada and the northern United States, leaving behind glacially scoured valleys, moraines1, eskers2 and glacial till.3

Northeast Extend of Larentide Ice Sheet During the Late Wisconsinan Stage

Did You Know?

The Laurentide Ice Sheet was up to two miles thick. Mount Washington, at 6,288 feet, is the highest peak in Northeastern United States and during the Wisconsin ice age it was blanketed in ice a mile thick! 4

As the detailed maps below indicate, Mianus River Park's soil is a direct result of the actions of the glacier. The surficial and soil parent maps clearly exemplify the overwhelming influence of how the massive weight and subsequent melting retreat of the huge ice sheet created the landscape and soil present today.

1 Till - http://en.wikipedia.org/wiki/Glacial_till

2 Moraine - http://en.wikipedia.org/wiki/Moraines

3 Esker - http://en.wikipedia.org/wiki/Eskers

4 Source: About Lake Hitchcock (Article and Map)

Soil Maps

The CT ECO map library is a comprehensive online explanation of Connecticut's natural resource and environmental information. All soil information included in the CT ECO map library is from the Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS), which is based on information originally published on the set of Soil Survey quarter quadrangle maps that cover Connecticut.

Inland and Wetland Soils

Wetland Soils include "any of the soil types designated as poorly drained, very poorly drained or alluvial and floodplain." The minimum size delineation is approximately 3 acres.

An on-site examination of the soil profiles by a Certified Soil Scientist is necessary to confirm the presence of soil designated as Inland Wetlands.

Soil Drainage

Soil Drainage refers to the frequency and duration of "natural" wet periods (man-made interventions such as constructed drainage or irrigation are NOT considered). Seven classes of natural soil drainage are recognized:

  • Excessively drained

  • Somewhat excessively drained

  • Well drained

  • Moderately well drained

  • Somewhat poorly drained

  • Poorly drained

  • Very poorly drained

These classifications are derived from observations of water tables, soil wetness, landscape position and soil morphology. In many soils, the depth and duration of wetness are related to the quantity nature and pattern of redoximorphic features. Redoximorphic features are soil characteristics associated with wetness and result from the reduction and oxidation of iron and manganese compounds in the soil after changes in water saturation.

Soil Parent

Parent Material is the term for the general physical, chemical and mineralogical composition of the soil formation. Many soil properties relate to parent material. Proportions of sand, silt and clay, types and amounts of rock fragments, density and structure of the soil are all important parameters in determining the correct soil parent.

A soil surveyor uses parent material to help interpret soil boundaries and the performance of the material below the soil.

Surficial Materials

Most of the deposits that overlie the bedrock surface of Connecticut are derived from glaciers and can be divided into two broad categories:

  • Glacial Ice-Land Deposits (tills and moraine) exposed uplands; and

  • Glacial Meltwater Deposits (stratified deposits) which are concentrated in the valleys and lowands.

Glacial Ice-Land Deposits (tills and moraine) primarily consist of sand, silt and boulders. These were derived directly from the ice and generally drain poorly. They are the most widespread surficial deposit on Connecticut.

Glacial Meltwater Deposits (stratified deposits) on the other hand were laid down in glacial streams and lakes which occupied the valleys in Connecticut as the last huge ice sheet melted away to the north. They often consist of layers of sands, gravels and clays with very few boulders. They are more permeable and make better aquifers than ice-laid deposits.

In addition, Connecticut's has scattered throughout the state, Post Glacial Sediments which are primarily floodplain sand, silt and and swamp deposits. They are typically thinner than the glacial deposits they overlie.

Deposits of floodplain alluvium are largely composed of sands, gravels and silts that have been reworked from glacial deposits but are mixed which organic material which greatly increases their fertility.


* Alluvium (from the Latin, alluvius, from alluere, "to wash against") is loose, unconsolidated (not cemented together into a solid rock) soil or sediments, which has been eroded, reshaped by water in some form, and redeposited in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel.