On August 2, 1790, the United States conducted its first census, pursuant to Article I, Section 2 of the United States Constitution. In the 230 years since, many changes have been made to the census – from its schedule to its counting process to its questions. Sno-Isle Libraries's Census Historical Timeline chronicles many of these changes and key events in U.S. Census history. The timeline is broken down by decade (to correspond with each census taken between 1790 and 2010), and the sections include links to the United States Census Bureau's historical archives, which provide a more in-depth look at each time period. Highlights include 1850, when the names of all members of a household were recorded (rather than just the head of household); 1960, when census questionnaires were first delivered to people through the mail; and 1990, when "extensive public television, radio, and print advertising" promoted the importance of the census. On the left-hand side of the page, readers will find additional census information, including a 2020 Census "Questionnaire Sample" (available in English and Spanish).