The Alexandria Historic District is a National Historic Landmark District in Alexandria, Virginia. Encompassing all of the city's Old Town and some adjacent areas, this area contains one of the nation's best-preserved assemblages of the late-18th and early-19th century urban architecture. The district was locally designated in 1946 and was declared a Natio…The Alexandria Historic District is a National Historic Landmark District in Alexandria, Virginia. Encompassing all of the city's Old Town and some adjacent areas, this area contains one of the nation's best-preserved assemblages of the late-18th and early-19th century urban architecture. The district was locally designated in 1946 and was declared a National Historic Landmark in 1966.