United States population censuses were taken in 1790 and every 10th year thereafter. Population schedules are available 72 years after the enumeration due to privacy reasons, so the most current population census currently available is from 1940.
U.S. federal census records for Connecticut are available online through different databases, such as Ancestry.com, the FamilySearch website, Fold3, and HeritageQuest. The 1850 census was the first to give the name and age of every person in the household. Before 1850, only the name of the head of household is given, all other individuals are merely counted - i.e., 1 male between the ages of 5 and 10, etc.