The town of Carr was established by the Union Pacific Railroad in 1872. Carr was named for Robert E. Carr of the Union Pacific, who managed the construction of the rail line through the town. The Carr Post Office opened on March 26, 1872.  From 1920 until 1939, the town carried Old Colorado State Highway 5, Which was meant as an access route. However, during this time, routes numbered 1-19 were major cross state highways, making it a some-what useless route.