The Carman's River is the main defining natural feature of the Brookhaven and South Haven Hamlets. It is one of the four largest rivers on Long Island and, like other Long Island rivers, is totally groundwater generated. Much of the upper river is protected by the Central Long Island Pine Barrens. All of it is designated by New York State as either a "Scenic River" or a "Recreational River."

The Carman's River is often eroneously reported as being named after Sam Carman (see People reference), 19th century proprietor of the mills on the river at South Haven, and host of a well known inn frequented by sportsmen from New York City and elsewhere. The river was instead renamed from the original Connecticut River to the Carman's River by William Smith "Tangier" after his wife Hannah Carman (see People reference), sister to Samuel Carman, and daughter of the Samual Carman who purchased the mills (along with other investors) shortly after the Revolutionary War. William Smith was the proprietor of the very large estate mostly on the east side of the river. He also claimed ownership of the river, based on the family colonial manorial grant – the Manor of St. George.

The original name, Connecticut, is often said to have been named after the colony and state of Connecticut, because some early settlers were from that side of the Long Island Sound. The river actually got its name from one of several English language variations of an Indian word (Quinnehtukqut, Connetquet, Connecticut) meaning “beside the long tidal river.” The name was applied by the native peoples to the river to the west, Connetquet in the Town of Islip, this river in the Town of Brookhaven, and to the river in what is now New England, stretching from the Long Island Sound to lakes in northern New Hampshire.

This fact sheet is being developed.