Gross gaming revenue from sports wagering in June amounted to $17.6m (£12.7m/€14.9m), up 15.8% from $15.2m recorded in May this year and 700.0% higher than $2.2m in June last year.
Online betting accounted for $19.5m of sports wagering revenue in June, compared to just $195,946 from retail sportsbooks in the state.
In terms of spending, players bet $229.8m on sports in June, down 10.1% from $249.0m in May and the lowest monthly amount of the calendar year to date.
A total of $227.1m was wagered with online operators, while the remaining $2.7m was bet at retail sportsbook facilities.
Basketball remained the most popular sports to wager on in Colorado, attracted $74.9m in total bets during the month.