The Twin Bores

Information about the the Eisenhower/Johnson Memorial Tunnels, which were designed as "twin bores"

The Eisenhower/Johnson Memorial Tunnels were designed as "twin bores".  Construction on the first bore (North Tunnel) began March 15, 1968 and was completed five years later on March 8, 1973.  This westbound bore was originally called the Straight Creek Tunnel, and later was officially named the Eisenhower Memorial Bore.  Construction on the second bore (South Tunnel) began August 18, 1975 and was completed four years later on December 21, 1979.  This eastbound bore was named after Edwin C. Johnson, a past Governor and U.S. Senator who had actively supported an interstate highway system across Colorado.