Rockville is a city in and the county seat of Montgomery County, Maryland, United States, and is part of the Washington metropolitan area. The 2020 census tabulated Rockville's population at 67,117, making it the fourth-largest incorporated city in Maryland. Rockville, along with neighboring Gaithersburg and Bethesda, is at the core of the Interstate 270 Technology Corridor which is home to numerous software and biotechnology companies as well as several federal government institutions.