Every 10 years, the U.S. Census Bureau conducts a census to count every resident in the United States. The census is conducted in years ending in zero, and the reference day for the next census will be April 1, 2020 ─ Census Day! In 2020, we are providing three modes of response so everyone will be able to respond the way they prefer: either anytime, anywhere through the Internet, or over the phone or by returning a paper questionnaire.
The data collected by the decennial census are used to determine the number of seats each state has in the U.S. House of Representatives. The first U.S. census was in 1790 during the first term of our first president, George Washington. Secretary of State Thomas Jefferson led the effort. The population counted was 3,929,625. Congress used these results to apportion 105 seats among the 15 states.
Hat tip for this blog: U.S. Census Day web post
2020 Census: U.S. Census Day portal