Old Georgetown Road is part of the original highway between Rockville and Georgetown. This course was used by portions of General Edward Braddock's army from Alexandria, Virginia, to Cumberland, Maryland, prior to the start of the ill-fated Braddock Expedition in 1755. The Rockville and Georgetown Turnpike, which opened in 1818, included a descent into the valley of Rock Creek that bypassed MD 187's portion of the Rockville–Georgetown highway. The portion of Old Georgetown Road from that turnpike (now MD 355) in Bethesda to the community of Alta Vista at Cedar Lane was paved as a macadam road by Montgomery County with state aid by 1910. MD 187 was extended to what is now Democracy Boulevard in 1924. The highway was extended as a macadam road to Tuckerman Lane in 1928. MD 187 was completed with a concrete section northeast to U.S. Route 240 (now MD 355) in 1929.