Colo. Rev. Stat. § 30-5-119
The county of Dolores is hereby created and established, with the legal capacities and functions of other counties of this state, and with boundaries as follows:
Commencing at the summit of the mountain known as the "Lizard's Head," near the headwaters of the Lake Fork of the San Miguel river, in the present county of Ouray; thence westward from the summit of said mountain along the summit of the range dividing the waters of the San Miguel and Dolores rivers to the summit of Lone Cone mountain; thence west to the western line of the state of Colorado; thence south along said western line to the north line of Montezuma county; thence east along said north line to the southwest corner of San Juan county; thence northeast along the summit of the range dividing the waters of the South Fork of Dolores river from the waters of Hermosa and Cascade creeks to the summit of the range at the head of the East Fork of the Dolores river; thence northeast along the summit of the range dividing the waters of said South Fork of Dolores river from the waters of the Lake Fork of the San Miguel river to the summit of said range south of the pass now crossed by the trail from the Fish lakes to Rico; thence from the summit of said range on a direct line to the summit of said "Lizard's Head" mountain, the place of beginning.
C.R.S. § 30-5-119