Colorado
- History
- 1866 City of Denver Business Directory
- Anasazi Heritage Center
- Boulder Carnegie Branch Library for Local History
- Boulder History Museum
- COGenWeb
- Colorado Firsts
- Colorado Historical Society
- Colorado History.com
- Colorado Lore, Legend, & Fact
- Colorado Springs Pioneer Museum
- Colorado Springs Pioneer Museum Collection Database
- Colorado State Archives
- Colorado State Archives Online Indexes
- Cyndi's List of Genealogy Sites on the Internet: Colorado
- Douglas County History Research Center
- Google: Colorado - History
- Grand County Historical Association
- Guide to Colorado Architecture
- Heritage West
- HeritageAspen: Aspen Historical Society
- Historic Georgetown
- Historical Guide to Colorado Architects
- Leadville, Colorado Area History Directory
- Littleton History
- Molly Brown House Museum
- Museum of Western Colorado
- Old Colorado City Historical Society
- Putting Together Colorado Territory
- Digital Image Collection at Denver Public Library
- Yahoo!: Colorado - History