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Census History: Civil War Sesquicentennial

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This month begins the sesquicentennial – the 150th anniversary – of the Civil War. The war began on April 12, 1861, when Confederate troops opened fire on Fort Sumter, near Charleston, SC.

Data collected by the US Census Bureau help paint a portrait of our nation during 1861. For example:

  • The censuses of 1850 and 1860 asked questions about freed and escaped slaves, and revealed that more slaves were freed in 1860 than in 1850. In addition, the number of slaves who escaped from Mississippi, Missouri, and Virginia increased in 1860, compared to 1850.
  • The 1860 Census, taken before the start of the Civil War, recorded nearly 4 million slaves in the nation.
  • The 1890 Census counted over 1 million surviving Union soldiers, sailors, and marines, and 432,000 surviving Confederate soldiers and sailors.

Based on data from the 1860 census, this map was the Census Bureau’s first attempt to map population density. It is a precursor to population density maps that have been produced since the 1870 census and in the Statistical Atlas, first published in 1874.

This Month in Census History

The U.S. Census Bureau conducted the 1930 Census on April 1, 1930. Until 1830, Census Day was in August. In 1920, the Census Bureau conducted the census on January 1 to more efficiently collect agricultural data. However, the 1929 Act authorizing the fifteenth census moved Census Day to April 1, where it remains today.

Did You Know?

Public Law 94-171, signed into law by President Ford in 1975, requires the U.S. Census Bureau to provide redistricting data to the states by April 1 of the year following the decennial census. The Census Bureau provides population counts for racial and ethnic groups and individuals of voting age. These data help states realign legislative districts to achieve equal representation in compliance with the Voting Rights Act of 1965.

2010 Census redistricting data for all 50 states, the District of Columbia and Puerto Rico were released before April 1 this year.

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