Paper: Letter (8.5in x 11in)
COLORADO DEPARTMENT OF REVENUE
DENVER CO 80261-0009
Due on the last day of March when filing online.
Payable to "Colorado Department of Revenue"
If the business closes during the year, then this is due within 30 days of the payment of the final wages or discontinuation of business.
To transmit forms W-2 and/or 1099 to the state.
Colorado Department of Revenue
Tax Information Call Center: (303) 238-7378