The Eisenhower Memorial Tunnel, about 60 miles west of Denver on Interstate 70, sits at 11,013 feet at the East Portal and 11,158 feet at the West Portal. The Tunnel traverses through the Continental Divide at an average elevation of 11,112 feet. When initially opened in the 1970s, the tunnel was not only the highest vehicular tunnel in the U.S., but it was also the highest in the world at that time. The facility lies entirely within the Arapaho National Forest and is divided by two counties, Clear Creek County at the East Portal and Summit county at the West Portal. The Tunnel and the Continental Divide also separate two watersheds, the Clear Creek Watershed on the east and the Straight Creek Watershed on the west.