The U.S. Census Bureau counts each resident of the country, where they live on April 1, every ten years ending in zero. The Constitution mandates the enumeration to determine how to apportion the House of Representatives among the states.
For the past several censuses, the Census Bureau has invited people to self-respond before following up in-person using census takers. The 2010 Census invited people to self-respond predominately by returning paper questionnaires in the mail. The 2020 Census allows people to self-respond in three ways: online, by phone, or by mail.
The 2010 Census self-response rates are final self-response rates mapped to current census geographies. The final self-response rate includes all housing units who self-responded to the census at any time during the enumeration. State and county rates have been coded with the official 2010 Census self-response rates. Any sub-geography that has the same boundary as a state or county also has been coded to the official 2010 Census self-response rate of that state or county. Self-response rates released following the 2010 Census are considered the “official” 2010 Census self-response rates.
The 2020 Census self-response rates are self-response rates rates for current census geographies. These rates are the daily and cumulative self-response rates for all housing units that received invitations to self-respond to the 2020 Census. The daily and cumulative 2020 self-response rates include both overall self-response rates (i.e. online, phone, and mail) and online self-response rates. The map was updated once a day at 3:00 pm EDT seven days a week from March 20 to May 31 and then five days a week after that through October 14th. There were no updates to the data and map on Friday, July 3, 2020 and Monday, September 7, 2020 due to federal holidays. A final map posting will occur on February 3, 2021.
The 2010 and 2020 Census self-response rates are available for states, counties, census tracts, congressional districts, towns and townships, consolidated cities, incorporated places, tribal areas, and tribal census tracts.
More information about these data are available in the Self-Response Rates Map Data and Technical Documentation document associated with the 2020 Self-Response Rates Map or review our FAQs.