Following the disruption of the American Revolutionary War, most of the Mahican descendants first migrated westward to join the Iroquois Oneida on their reservation in central New York. The Oneida gave them about 22,000 acres for their use. After more than two decades, in the 1820s and 1830s, the Oneida and the Stockbridge moved again, pressured to relocate to northeastern Wisconsin under the federal Indian Removal program. The tribe's name came from where they lived: "Muh-he-ka-neew" (or "People of the continually flowing waters.") The word Muh-he-kan refers to a great sea or body of water and the Hudson River reminded them of their place of origin, so they named the Hudson River "Seepow Mahecaniittuck," or the river where there are people from the continually flowing waters. Therefore, they, along with tribes also living along the Hudson River (like the Munsee and Wappinger), were called "the River Indians" by the Dutch and English. The Dutch heard and wrote the term for the people of the area variously as: Mahigan, Mahikander, Mahinganak, Maikan and Mawhickon, which the English simplified later to Mahican or Mohican. The French, through their Indian allies in Canada, called the Mahicans Loups (or wolves) just as they called the Iroquois the "Snake People," (or "Five Nations.") Like the Munsee and Wippingers, the Mahicans were related to the Lenape People of the Delaware River valley.
The Mahican were living in and around the Mahicannituck ("Their name for the Hudson River"), along the Mohawk River and Hoosic River at the time of their first contact with Europeans after 1609, during the settlement of New Netherland. In their own language, the Mahican referred to themselves collectively as the "Muhhekunneuw", "people of the great river". The Mahican territory was bounded on the northwest by Lake Champlain and Lake George and on the northeast by the Pocomtuc Confederacy, Pennacook Confederacy (also known as Merrimack or Pawtucket) and the Connecticut River Valley, which was inhabited by the Sokokiof the Western Abenaki. The original Mahican homeland was the Hudson River Valley from the Catskill Mountains north to the southern end of Lake Champlain. Bounded by the Schoharie River in the west, it extended east to the crest of the Berkshire Mountains in western Massachusetts from northwest Connecticut north to the Green Mountains in southern Vermont.
Mahican villages were fairly large. Usually consisting of 20 to 30 mid-sized longhouses, they were located on hills and heavily fortified. Large cornfields were located nearby. Agriculture provided most of their diet but was supplemented by game, fish, and wild foods. Mahican villages were governed by hereditary sachems advised by a council of clan elders. A general council of sachems met regularly at Shodac (east of present-day Albany) to decide important matters affecting the entire confederacy.