The Dyer River is a 20.2 miles (32.5 km) river in Maine

Maine

Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

. It originates along the northern boundary of the town of Jefferson

Jefferson, Maine

Jefferson is a town in Lincoln County, Maine, United States. The population was 2,388 at the 2000 census.-History:Jefferson is a town in Lincoln County, incorporated on February 24, 1807, when Thomas Jefferson was President, from Ballstown Plantation...

 with the town of Somerville

Somerville, Maine

Somerville is a town in Lincoln County, Maine, United States. The population was 509 at the 2000 census.-Geography:According to the United States Census Bureau, the town has a total area of , of which, of it is land and of it is water....

 (44.2370°N 69.4700 °W) and flows southwesterly through Jefferson, passing through Dyer Long Pond and near South Jefferson. It continues southwest into the town of Newcastle

Newcastle, Maine

Newcastle is a town in Lincoln County, Maine, United States. The population was 1,748 at the 2000 census. The village of Newcastle is located in the western part of the town, on the Damariscotta River...

, passing the villages of North Newcastle and Sheepscot, where it joins the tidal Sheepscot River

Sheepscot River

The Sheepscot River is a river in the U.S. state of Maine. Its lower portion is a complex island estuary with connections to the Kennebec River downstream of Merrymeeting Bay.-Route:...

.