The Historical Collections holds the complete federal census for the state of Connecticut.
Some censuses are available full text on CD ROM, ask librarian.
Nearly the entire U.S. census for 1890 was destroyed in a fire around the turn of the century. Consequently, there are no available population rolls for Connecticut for the year of 1890. Printed indexes are available for 1800-1870 censuses. There is no printed index or Soundex for the 1910 Connecticut census. The 1880 soundex only lists households which contained children 10 years old or younger.