Dyer Mountain is a high mountain summit in the Mosquito Range of the Rocky Mountains of North America. The 13,862-foot (4,225 m) thirteener is located 5.9 miles (9.5 km) east (bearing 95°) of the City of Leadville, Colorado, United States, on the drainage divide separating Lake County from Park County. The mountain was named in honor of frontier preacher John Lewis Dyer.