Busk-Ivanhoe Tunnel was a 9,394 ft (2,863 m) long railroad tunnel at an elevation of 10,953 ft (3,338 m) in Colorado. It was built by the Busk Tunnel Railway Company for the Colorado Midland Railroad in 1891 as a replacement for the Hagerman Tunnel at a lower, more direct route.
The tunnel was briefly abandoned following Colorado Midland's 1897 bankruptcy, but returned to use a few years later.
Since 1962, the tunnel has been used as part of the Fryingpan-Arkansas Project to carry water across the Continental Divide. It presently moves water between Ivanhoe Lake and Busk Creek.