Brookeville is a town in Montgomery County, Maryland, located 20 km (12 mi) north of Washington, D.C., and 2 km (1.2 mi) north of Olney. Brookeville was settled by Quakers late in the 18th century and was incorporated as a town in 1808. Historically a farming town, Brookeville is now at the northern edge of the densely developed Washington suburbs. The population was 166 at the 2020 census.

Montgomery County is the most populous county in the U.S. state of Maryland. As of the 2020 census, the county's population was 1,062,061, increasing by 9.3% from 2010. The county seat is Rockville and Germantown is the most populous place in the county. The county is adjoined to Washington, D.C., the nation's capital, and is part of the Washington metropolitan area and the Washington–Baltimore combined statistical area. Most of the county's residents live in Silver Spring, Bethesda, Germantown, and the incorporated cities of Rockville and Gaithersburg.