Colorado - Criteria: A (event)
| 7-D School |
| Adams County Courthouse |
| Adobe Stables, Arkansas Valley Fairgrounds |
| Akron Gymnasium |
| Alamo Hotel |
| Alamo Placita Park |
| Alamosa County Courthouse |
| Alamosa Post Office |
| Alger, Amanda K., Memorial Methodist Episcopal Church |
| All Saints Church of Eben Ezer |
| Alpine Tunnel Historic District |
| Altamaha Apartments |
| American Legion Hall |
| American National Bank Building |
| Ammons Hall |
| Ammunition Igloo |
| Animas Forks |
| Annunciation Church |
| Ansel Hall Ruin |
| Antlers Cafe and Bar |
| Arapahoe Acres |
| Arapaho Hills |
| Arcanum Apartments |
| Argo Tunnel and Mill |
| Armory Hall, Fraternal Hall |
| Armstrong Hotel |
| Arrowhead Lodge |
| Art Building |
| Arvada Downtown |
| Arvada Flour Mill |
| Ashcroft, Colorado |
| Aspen Community Church |
| Astor House Hotel |
| Austin Building |
| Avoca Lodge |
| Baca House and Outbuilding |
| Bain Cabin |
| Baldpate Inn |
| Bauer Bank Block |
| Baur Confectionery Company |
| Bear Creek Canyon Scenic Mountain Drive |
| Beaumont Hotel |
| Beaver Creek Massacre Site |
| Beckwith Ranch |
| Beecher Island Battleground |
| Bee Farm |
| Bell and Canant Mercantile-Crossan's M and A Market |
| Bell Mercantile |
| Bemis Hall |
| Benevolent and Protective Order of Elks Lodge |
| Bent County Courthouse and Jail |
| Bent County High School |
| Bent's Old Fort National Historic Site |
| Bergen Park |
| Big Thompson River Bridge III |
| Big Thompson River Bridge IV |
| Bimson Blacksmith Shop |
| Black Forest School |
| Black Squirrel Creek Bridge |
| Bluebird Theater |
| Blue Jay Inn |
| Boat Tow |
| Boggsville |
| Bonfils Memorial Theater |
| Boreas Railroad Station Site |
| Boston Building |
| Botanical and Horticultural Laboratory |
| Boulder County Poor Farm |
| Boulder Creek Bridge |
| Boulder Crescent Place Historic District |
| Boulder Valley Grange No. 131 |
| Bouvier-Lothrop House |
| Bowles House |
| Bowman, William Norman, House-Yamecila |
| Brannan Sand and Gravel Pit #8-Lake Sangraco Boathouse Complex |
| Bridge over Fountain Creek |
| Brighton High School |
| Brinker Collegiate Institute |
| Bromide Charcoal Kilns |
| Bromley Farm-Koizuma Hishinuma Farm |
| Brook Forest Inn |
| Bross Hotel |
| Brown, J. S., Mercantile Building |
| Brueger Brothers Building and Annex |
| Brush, Jared L., Barn |
| Buchtel Bungalow |
| Buckeye School |
| Bunce School |
| Burgess House |
| Burlington Gymnasium |
| Burlington Hotel |
| Burlington State Armory |
| Butler House |
| Calhan Rock Island Railroad Depot |
| Campbell, Richard Crawford, House |
| Camp George West Historic District |
| Camp Hale Site |
| Canon City Downtown Historic District |
| Canon City State Armory |
| Canon Pintado |
Data from United States Park Service and Wikidata
