Colo. Const. art. VIII, § 2
The general assembly shall have no power to change or to locate the seat of government of the state, which shall remain at the city and county of Denver.
Source: Entire article added, effective August 1, 1876, see L. 1877, p. 53. L. 88: Entire section amended, p. 1454, effective upon proclamation of the Governor, L. 89, p. 1657, January 3, 1989.