Colorado - Significance region: Local
| 655 Broadway Building |
| 7-D School |
| Adams County Courthouse |
| Adobe Stables, Arkansas Valley Fairgrounds |
| Akron Gymnasium |
| Alamo Hotel |
| Alamosa County Courthouse |
| Alamosa Post Office |
| Alexander House |
| Alger, Amanda K., Memorial Methodist Episcopal Church |
| Altamaha Apartments |
| American Federation of Human Rights Headquarters |
| American Legion Hall |
| American National Bank Building |
| Ammunition Igloo |
| Anderson Barn |
| Anderson, Peter, House |
| Animas Canon Toll Road |
| Animas City School |
| Animas Forks |
| Annunciation Church |
| Antelope Springs Methodist Episcopal Church |
| Antlers Cafe and Bar |
| Arapahoe Acres |
| Arapaho Hills |
| Arcanum Apartments |
| Argentum Mining Camp |
| Armory Hall, Fraternal Hall |
| Armstrong Hotel |
| Arnett-Fullen House |
| Arno Apartments |
| Art Building |
| Artesia Farm |
| Arvada Downtown |
| Arvada Flour Mill |
| Aspen Community Church |
| Atchison, Topeka and Santa Fe Railway Passenger Depot |
| Atwater, Samuel H., House |
| Aultman House |
| Auraria 9th Street Historic District |
| Austin Building |
| Avery House |
| Avoca Lodge |
| Baca Land Grant No. 4-Baca Ranch Rural Historic Landscape |
| Bachelor-Commodore Mine Complex |
| Bachelor Mine |
| Bailey House |
| Bain Cabin |
| Baker House |
| Baldpate Inn |
| Ball, Elmer and Etta, Ranch |
| Bancroft, Caroline, House |
| Barker, Hannah, House |
| Barker House |
| Barndollar-Gann House |
| Barnes-Peery House |
| Bastien's Restaurant |
| Bats Grocery Store |
| Battlement Mesa Schoolhouse |
| Bauer Bank Block |
| Baugh, James H., House |
| Baur Confectionery Company |
| Baxter House |
| Bear Canon Agricultural District |
| Bear Creek Canyon Scenic Mountain Drive |
| Beaumont, Allen, J., House |
| Beaumont Hotel |
| Beaver Creek Massacre Site |
| Beckwith Ranch |
| Bee Farm |
| Behrman Ranch |
| Belcaro |
| Bell and Canant Mercantile-Crossan's M and A Market |
| Bell Mercantile |
| Bemis Hall |
| Bemis, Judson Moss, House |
| Benevolent and Protective Order of Elks Lodge |
| Bennett-Field House |
| Benson, A.S., House |
| Bent County High School |
| Bergen Park |
| Berger Cabin |
| Berkeley School |
| Big Thompson River Bridge III |
| Big Thompson River Bridge IV |
| Bimson Blacksmith Shop |
| Bingham Homestead Rural Historic Landscape |
| Black, Dr. John A., House Complex |
| Black Forest School |
| Black Squirrel Creek Bridge |
| Bloomfield Site |
| Bluebird Theater |
| Blue Jay Inn |
| Boat Tow |
| Bode-Stewart House |
| Boggs Lumber and Hardware Building |
| Bonfils Memorial Theater |
| Bonney, J. M., House |
| Borland, Maude Stanfield Harter, House |
| Boulder County Poor Farm |
Data from United States Park Service and Wikidata
