From The American Presidency Project, Proclamation 9929—Constitution Day, Citizenship Day, and Constitution Week, 2019: “The Congress, by joint resolution of February 29, 1952 (36 U.S.C. 106), designated September 17 as ‘Constitution Day and Citizenship Day,’ and by joint resolution of August 2, 1956 (36 U.S.C. 108), requested that the President proclaim the week beginning September 17 and ending September 23 of each year as ‘Constitution Week.’"

Source: 2019 American Community Survey (ACS), 1-Year Estimates.

Source: 2019 American Community Survey (ACS), 1-Year Estimates. 

From the Decennial Census of Population and Housing > About the Decennial Census:

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