The pass is a saddle between the San Juan Mountains to the south and the Uncompahgre Plateau to the north and divides the Uncompahgre River watershed from the San Miguel River watershed and Ouray County from San Miguel County.

The pass takes its name from Dallas Creek which drains the basin on the north side of Mount Sneffels into the Uncompahgre River.

The divide's namesake is George M. Dallas, 11th Vice President of the United States.

In 1890 the Rio Grande Southern Railroad was built over the divide from Ridgway to Telluride.

This Colorado state location article is a stub.