It is bordered by Savoy to the north, Plainfield to the northeast and east, Cummington to the southeast, Peru and Hinsdale to the south, Dalton to the southwest, and Cheshire to the northwest.

Windsor is located on a plateau in the Berkshire Hills, and lies near the source of the Westfield River.

The river runs southward through the northeastern part of town, flowing through Windsor State Forest.

One of the river's feeder brooks flows through the Windsor Jambs, a series of rocky waterfalls.

The population density was 25.0 people per square mile (9.7/km2), and ranks 25th in the county and 334th in the commonwealth.

Windsor employs the open town meeting form of government, and is led by a board of selectmen.

The town has its own services, including police, fire and public works departments.

In the Massachusetts Senate, the town is part of the Berkshire, Hampshire and Franklin district, represented by Ben Downing, which includes all of Berkshire County and western Hampshire and Franklin counties.

[15] The town is patrolled by the Fourth (Cheshire) Station of Barracks "B" of the Massachusetts State Police.

Windsor is a member town of the Central Berkshire Regional School District.