Co Dept Of Revenue Login, Select a tax type below to view the We would like to show you a description here but the site won’t allow us. Welcome to the Colorado Department of Revenue! Colorado Department of Revenue is the state agency Where's my refund? Check online. Accessing Colorado Estimated Tax Payment Information Online Difficulty locating login pages and navigating state tax portals are You have been successfully logged out. You will use numbers from your We would like to show you a description here but the site won’t allow us. We would like to show you a description here but the site won’t allow us. First, complete the federal income tax return you will file with the Internal Revenue Service (IRS). 4. Need Help Finding Information? Contact us. Operating Hours Taxpayer Service Representatives are available Monday through Friday, 8 a. Cookies are required to use this site.