Voter turnout is expected to be between 75 to 80 percent, compared to the average of 70 percent, the clerk's office said.

Many voters have already returned their ballots.

As of Monday, 113,932 ballots have been received, the Secretary of State's office said Monday. Of those, 48,030 were from Democrats, 36,790 from Republicans and 27,435 were from unaffiliated voters.

El Paso County voters have turned in the second-most ballots of any county in Colorado. Of the 15,673 ballots returned in the county, 6,973 are from Republicans, 4,564 from Democrats and 3,804 from independents. Only 70 Teller County ballots had been returned as of Monday. Arapahoe County has seen the state's most returns, with 16,244. Denver County has had 15,972 ballots submitted.