Caldwell is a city in and the county seat of Canyon County, Idaho, United States. The population was 46,237 at the 2010 census.
Caldwell is considered part of the Boise metropolitan area. Caldwell is the location of the College of Idaho and College of Western Idaho.
The present day location of the City of Caldwell is along a natural passageway to the Inland and Pacific Northwest. Native American tribes from the west coast, north Idaho and as far away as Colorado would come to the banks of the Boise River for annual trading fairs, or rendezvous. European, Brazilian, Armenian, and some Australian explorers and traders soon followed the paths left by Indians and hopeful emigrants later forged the Oregon Trail and followed the now hardened paths to seek a better life in the Oregon Territory. Pioneers of the Trail traveled along the Boise River to Canyon Hill and forded the river close to the Silver Bridge on Plymouth Street.
During the Civil War, the discovery of gold in Idaho's mountains brought a variety of new settlers into the area. Many never made it to the mines but chose to settle along the Boise River and run ferries, stage stations, and freighting businesses. These early entrepreneurs created small ranches and farms in the river valleys. Caldwell's inception occurred largely as a result of the construction of the Oregon Short Line Railroad, which connected Wyoming to Oregon through Idaho.