Colo. Rev. Stat. § 37-31-114
No registration shall be required for any election, but no person shall be entitled to vote without the qualifications prescribed in section 37-31-109. Any judge of election or any voter at the polls has the right of challenging anyone seeking to vote at said election on the ground of said person's disqualification; and, before such challenged person is entitled to vote, he shall take an oath, to be administered by one of the judges of election, to the effect that he is a qualified elector to vote at said election. Anyone making a false oath at said election is guilty of perjury in the second degree. The polls for said election shall be open in each of the precincts from 7 a.m. to 7 p.m., and, after said polls are closed, the judges of said election shall canvass the votes and make returns thereof, one copy to be retained by said judges and the other certified to the board of directors.
C.R.S. § 37-31-114
For perjury in the second degree, see § 18-8-503.