Historic Airports and Airlines (1)

Airfields, Airports, Airlines, and anything related to flying

Historic Amusement Parks (4)

Historic Automobile, Carriage, and Wagon Companies (34)

Historic Bank Buildings (32)

Historic Barns (60)

Historic Breweries (44)

Breweries, Distilleries, and anything related to the manufacture of alcoholic beverages

Historic Bridges (108)

Historic Cemeteries (36)

Historic Church Buildings (94)

Historic City Halls (10)

Historic Commercial Buildings (137)

Historic Communications Facilities (11)

Historic Community Buildings (20)

Historic Courthouse Buildings (11)

Covered Bridges (347)

Historic Customs Houses (1)

Historic Department Stores (54)

Fire Watchtowers - Lookout Towers (8)

Historic Grain Elevators (10)

Historic Hospitals and Medical Facilities (33)

Historic Hotels (161)

Historic Houses (682)

Mansions of the Gilded Age (8)

Historic Hydroelectric Power Plants (24)

Historic Industrial Buildings (235)

Historic Library Buildings (14)

Historic Lighthouses (142)

Historic Mansions and Estates (198)

Historic Meeting House and Fraternal Lodge Buildings (13)

Historic Military Facilities (5)

Historic Mills (58)

Historic Mines (4)

Historic Apartment buildings (16)

Historic Museums and Galleries (11)

Historic Office Buildings (41)

Historic Farms and Plantations (223)

Historic Police Stations (1)

Historic Post Office Buildings (9)

Historic Power Plant Buildings (30)

Facilities related to the generation of electricity

Historic Prisons and Jails (7)

Historic Recreation Facilities (6)

Historic Restaurants and Food Stands (6)

Historic Retail Buildings and Department Stores (99)

Historic Roadside Attractions (22)

Round Barns (55)

Historic Route 66 (7)

Historic School Buildings (311)

Education Buildings including public and private K-12 buildings as well as College, University, and Vocational Education Buildings and Sites

Historic Gas and Service Stations (18)

Historic Special and Unique Structures (7)

Historic Stadiums and Arenas (9)

Historic Steel Mills and Related Facilities (4)

Historic Textile Mills (26)

Historic Theaters (69)

Historic Railroad - Train Stations (234)

Train Depots, Rail Yards and repair faclities, Railroad Bridges and Tunnels, and everything else related to Trains

Historic Warehouse Buildings (7)