unincorporated community, Montgomery county, central Maryland, U.S., a northern residential suburb of Washington, D.C. It was once the site of the estate of journalist and politician Francis Preston Blair (Blair, Francis Preston, Jr.) (1791–1876), whose son, Montgomery, served as postmaster general in Abraham Lincoln's cabinet. It derived its name from a local spring, the bottom of which sparkled with flakes of mica. Population growth occurred mainly after World War II. The headquarters of the National Association of the Deaf, the International Fabricare Institute, the Forest Glen Annex to the Walter Reed Army Medical Center, the Seventh-day Adventist World Headquarters, and the National Capital Trolley Museum are located there.