A
- abandoned buildings (5)
- abutments (3)
- accessory industrial buildings (34)
- adaptive reuse (37)
- adits (2)
- administration buildings (85)
- administrative agencies (23)
- adobe buildings (113)
- adobe houses (20)
- advertisements (photocopies) (1)
- aerial tramways (3)
- aeronautics (1)
- African Americans (107)
- aged persons (11)
- aging (2)
- agricultural equipment (1)
- agricultural facilities (1)
- agricultural land (2)
- agriculture (782)
- aids to navigation (3)
- air bases (8)
- air compressors (2)
- air raid shelters (5)
- aircraft industry (26)
- aircraft (40)
- airfields (3)
- airplane industry (1)
- airports (6)
- allées (1)
- alleys (7)
- almshouses (2)
- alteration (1)
- ammunition industry (19)
- ammunition (24)
- amphitheaters (2)
- amusement parks (4)
- Anglican churches (4)
- animal experimentation (8)
- animal housing (13)
- animal shelters (3)
- animal training (3)
- annealing furnaces (1)
- antennas (2)
- antique stores (3)
- apartment hotels (7)
- apartment houses (117)
- apartments (57)
- aprons (1)
- apses (1)
- aquatic sports (1)
- aqueducts (36)
- arbors (bowers) (1)
- arcades (architectural components) (2)
- arcades (shopping facilities) (6)
- arch bridges (294)
- archaeological sites (4)
- archaeology (30)
- arches (6)
- architects' offices (3)
- architects (6)
- architectural elements (87)
- architectural follies (3)
- archives (3)
- armies (102)
- armoires (1)
- armored vehicle industry (1)
- armories (27)
- arsenals (6)
- Art Deco architectural elements (14)
- Art Moderne architectural elements (1)
- artesian wells (1)
- artificial rubber industry (1)
- artificial ruins (1)
- artists' studios (2)
- artists (3)
- Arts & Crafts movement (2)
- Asian Americans (2)
- assaying (2)
- assembly plants (14)
- athletic fields (3)
- auctions (1)
- auditoriums (21)
- authors (3)
- automobile dealerships (4)
- automobile equipment & supply stores (3)
- automobile industry (13)
- automobile repair (8)
- automobile service stations (59)
- automobiles (1)
- awnings (3)