You do need
some kind of proof of ID. Below are the accepted forms of ID. Have also included a PDF of the State registration form. Print a few dozen copies out and keep them handy when you are out and about......
A valid Colorado driver's license; or
A valid Colorado Department of Revenue
identification card; or
A valid U.S. passport; or
A valid pilot's license with photograph issued
by the Federal Aviation Administration; or
A valid employee identification with a
photograph issued by the U.S. Government,
Colorado state government, or any county,
municipality, board, authority, or other
political subdivision of the state; or
A valid U.S. Military Identification card
with photograph; or
A copy of a current utility bill, bank statement,
government check, paycheck, or other
governmental document that shows the
name and address of the elector; or
At least the last four digits of the person's
social security number.
If the approved form of identification shows
an address, it must show your address as
being in the state of Colorado.http://www.co.arapahoe.co.us/CR/Election/Forms/voter_reg_form.pdf