The Great Divide

Somewhere in the mountains around you runs an invisible line that decides the fate of every raindrop. The Continental Divide splits North America's water between two oceans. Precipitation on the west side eventually reaches the Pacific.

Precipitation on the east side travels toward the Gulf of Mexico and the Atlantic. Colorado sits at the heart of it. The divide runs north to south through some of the highest terrain on the continent.

Its highest point anywhere in North America is Grays Peak in Colorado, at fourteen thousand two hundred seventy-six feet. Most travelers cross it through one of two tunnels. The Eisenhower and Johnson Memorial Tunnel, on Interstate Seventy about sixty miles west of Denver, bores under the divide at eleven thousand one hundred fifty-eight feet, the highest point on the entire Interstate Highway System.

The first bore opened in March of nineteen seventy-three. Farther north, the Moffat Tunnel has carried rail traffic under the mountains since nineteen twenty-eight, named for the railroad pioneer David Moffat, who died before his tunnel was finished. The divide also sets up one of Colorado's defining tensions: about eighty percent of the state's precipitation falls on the west side, while about eighty percent of the population lives on the east.

Squaring that gap has meant a century of dams, tunnels, and water law.