The rugged nature of Boulder Canyon challenged early road and rail engineers. While a stagecoach road was built up the canyon to the town of Nederland, the Colorado and Northwestern Railway opted to go up Four Mile Canyon to reach the mining towns of Gold Hill, Eldora and Ward.
|Boulder Canyon at Castle Rock||1900||Louis Charles McClure||DPL|
|Boulder Falls||1919||Philip Munz||University of Chicago|
|Stage Stop Near Boulder Falls||1880||J. B. Sturtevant||DPL|
|Boulder Hydro Power||1910||Louis Charles McClure||DPL|
|Boulder Canyon||1898||Louis Charles McClure||DPL|
|Lover's Leap||1898||Louis Charles McClure||DPL|