Belfast is a city located in Waldo County, Maine, serving as the county seat. Situated at the mouth of the Passagassawakeag River estuary where it meets Belfast Bay and Penobscot Bay, the city occupies a strategic coastal position in the state's midcoast region. According to the 2020 census, Belfast had a population of 6,938.
The city's geography along the confluence of the river estuary and Penobscot Bay has historically made it a maritime hub. Its role as the administrative center of Waldo County reflects its importance as a regional center in coastal Maine.