[1] This was the twenty-second federal census and was at the time the largest civilly administered peacetime effort in the United States.

Aggregate data for small areas, together with electronic boundary files, can be downloaded from the National Historical Geographic Information System.

Utah was extremely close to gaining a fourth congressional seat, falling 857 people short, which in turn was allocated to North Carolina.

The margin was later shortened to 80 people, after the federal government discovered that it overcounted the population of North Carolina by 2,673 residents.

The state challenged that the use of imputation violates the Census Act of 1957 and that it also fails the Constitution's requirement in Article I, Section 2 that an "actual enumeration" be used for apportionment.

[14] The census forms did not include any questions regarding sexual orientation, making it impossible to compile data comparing heterosexual and homosexual populations.

[15][16] Responses were tabulated and the Census Bureau reported that there were more than 658,000 same-sex couples heading households in the United States.

The lack of accurate numbers makes it difficult for lawmakers who are considering legislation on hate crimes or social services for gay families with children.

[20] Another issue that concerned gay rights advocates involved the automatic changing of data during the tabulation process.

This automatic software data compiling method, called allocation, was designed to counteract mistakes and discrepancies in returned questionnaires.

The Census Bureau explained that same-sex "Husband/wife" data samples were changed to "unmarried partner" by computer processing methods in 99% of the cases.

In the remaining 1%, computer systems used one of two possibilities: a) one of the two listed sexes was changed, making the partnership appear heterosexual, or b) if the two partners were more than 15 years apart in age, they might have been reassigned into a familial parent/child relationship.

The Act states: In determining the meaning of any Act of Congress, or of any ruling, regulation or interpretation of the various administrative bureaus and agencies of the United States, the word 'marriage' means only a legal union between one man and one woman as husband and wife, and the word 'spouse' refers only to a person of the opposite sex who is a husband or wife.