Brewer is a city in Penobscot County, Maine, United States. It is part of the Bangor, Maine Metropolitan Statistical Area. The city is named after its first settler, Colonel John Brewer. The population was 9,672 at the 2020 census.

Penobscot County is a county in the U.S. state of Maine, named for the Penobscot people in Wabanakik. As of the 2020 census, the population was 152,199, making it the third-most-populous county in Maine. Its county seat is Bangor. The county was established on February 15, 1816, from part of Hancock County when the area was still part of Massachusetts. Penobscot County is home to the University of Maine.