Mount Washington is a town in Berkshire County, Massachusetts, United States. It is part of the Pittsfield, Massachusetts Metropolitan Statistical Area. The population was 160 at the 2020 census, making it the least populous town in Berkshire County and, after Gosnold and Monroe, the third least populous in Massachusetts. The name of the town is a tribute to George Washington, who at the time of incorporation was Commander-in-Chief of the Continental Army during the American Revolutionary War.

Berkshire County is the westernmost county in the U.S. state of Massachusetts. As of the 2020 census, the population was 129,026. Its largest city and traditional county seat is Pittsfield. The county was founded in 1761. The Berkshire Hills are centered on Berkshire County. Residents are known as Berkshirites. It exists today only as a historical geographic region, and has no county government, with the exception of the retirement board for former county workers, and certain offices such as the sheriff and registry of deeds.