Interstate 25 (I-25) is a part of the Interstate Highway System that runs from Las Cruces, New Mexico, to Buffalo, Wyoming. In Wyoming, the Interstate Highway runs 300.530 miles (483.656 km) from the Colorado state line near Cheyenne north to its national terminus at I-90 near Buffalo. I-25 connects Wyoming's largest city and capital, Cheyenne, with its second largest city, Casper, and the smaller communities of Wheatland, Douglas, and Buffalo. The highway also connects those cities with Denver and Billings via I-90. I-25 runs concurrently with U.S. Route 87 (US 87) for almost its entire course in Wyoming. The highway also has extensive concurrencies with US 20 and US 26 along its east–west segment through the North Platte River valley. The Interstate has business loops through Cheyenne, C