The Territory of Colorado was represented by one non-voting delegate at-large to the United States House of Representatives from its organization in 1861, until statehood in 1876.
List of delegates
Upon admission to the Union on 1876, the State of Colorado was entitled to full representation in the United States Congress. See United States Congressional Delegations from Colorado and Colorado Congressional Districts.
References
Colorado Territory's at-large congressional district Wikipedia(Text) CC BY-SA