Casper, Wyoming, and Fort Collins, Colorado, are connected by more than 222 miles of Interstate 25. They're named for father-son soldiers Fort Collins for Lt. Col. William O. Collins and Casper for his son, 2nd Lt. Caspar Collins.
The Battle of Red Buttes in 1865 aka "Custard's Last Stand" was a small but significant skirmish that directly contributed to the Battle of Little Bighorn and the naming of Casper, Wyoming.