<Tr> <Th> Width </Th> <Td> 40 ft (12.2 m) each </Td> </Tr> <Tr> <Th> Grade </Th> <Td> 1.64% </Td> </Tr> <P> The Eisenhower Tunnel, officially the Eisenhower--Edwin C. Johnson Memorial Tunnel, is a dual - bore, four - lane vehicular tunnel in the western United States, approximately sixty miles (97 km) west of Denver, Colorado . The tunnel carries Interstate 70 (I - 70) under the Continental Divide in the Rocky Mountains . </P> <P> With a maximum elevation of 11,158 feet (3,401 m) above sea level, it is one of the highest vehicular tunnels in the world . The tunnel is the longest mountain tunnel and highest point on the Interstate Highway System . With the completion of the second bore in 1979, it was one of the last major pieces of the Interstate system to be completed . </P>

Where is the continental divide on i 70