Colorado is served by the Denver District. The office is located at 4730 Paris Street; Denver, CO 80239. The office is open from 7:30am until 2:30pm, Monday through Thursday. There is a long wait at the office, but all customers arriving prior to 2:00pm will be served. Click here to find the INS USCIS Immigration Forms you need! Click Here for Immigration Information, Reports, and Frequent Questions Click here to find the immigration books and manuals you need!