Distance: 17 miles from West Thumb Geyser Basin to Old Faithful area
Craig Pass is an important geologic landmark because it is here, at the Continental Divide in the Yellowstone-Teton area, that the headwaters of two major rivers are formed, one emptying into the Pacific Ocean, the other into the Gulf of Mexico. The Snake River winds from Grand Teton through Idaho to meet the Columbia River in Oregon and then drains into the Pacific Ocean at Astoria, Oregon. The Yellowstone River, which begins south of Yellowstone Park, drains into the Missouri River, which drains into the Mississippi, which empties into the Gulf of Mexico.
An interesting phenomenon takes place on the Old Faithful route at Isa Lake atop Craig Pass. Unlike most lakes and streams, it has both eastern and western drainages and ends up in both the Pacific Ocean and the Gulf of Mexico. Amazingly, as a consequence of a gyroscopic maneuver, the outlet on the east curves west and drains to the Pacific, and the outlet on the west curves east and drains to the Gulf.
Before you reach the Old Faithful geyser area, two additional detours are recommended. About 3 miles south of Old Faithful is an overlook at the spectacular Kepler Cascades, a 150-foot stair-step waterfall on the Firehole River.
Near that parking lot is the trail head for the second detour, the 4 1/2-mile round-trip Lonestar Geyser Trail. The geyser erupts every 3 hours, sending steaming water 30 to 50 feet from its 12-foot cone. The trail, which gently winds along the Firehole River through pastoral meadows and a forest, is a must-do; hiking, biking, and cross-country skiing are all popular. Even when others are on the trail, the area exudes a solitary air because it is possible to abandon the trail, follow the meandering stream, and find flat, open places to relax or picnic.
