Continental Divide Sign
When driving between Old Faithful and West Thumb you'll pass twice the Continental Divide signs. Isa Lake sits about halfway between the Old Faithful and West Thumb geyser basins on the Yellowstone National Park's Grand Loop Road. There is a small roadside pullout with informational signage. The road crosses the Continental Divide, this time at an elevation of 8,262 feet and again at 8,391 feet. Signs are posted at each of these locations designated as the Continental Divide. This makes it difficult to understand the divided concept or to visualize where the water is going. Maps show the Continental Divide as a thin line crossing irregularly from the park's western boundary to leave the park near the southeast corner. The Continental Divide (also known as the Great Divide) is the main watershed boundary of the North American continent.