Mattawamkeag is a census-designated place (CDP) and the primary village in the town of Mattawamkeag, Penobscot County, Maine, United States.

It is in the southwestern corner of the town, where the Mattawamkeag River joins the Penobscot.

U.S. Route 2 passes through Mattawamkeag, leading southwest 60 miles (97 km) to Bangor and northeast 65 miles (105 km) to Houlton.

Maine State Route 157 leads northwest from Mattawamkeag 14 miles (23 km) to East Millinocket.

Mattawamkeag was first listed as a CDP prior to the 2020 census.