How to narrow down date of U.S. census data collection before 1850? Starting in 1850, the U.S. census had a date at the top of the page for when the enumeration was recorded for the families on that page. I was looking at the 1830 census and 1840 census in Claiborne, Louisiana in particular and see on Wikipedia that those censuses were recorded as of June 1, 1830 and June 1, 1840. For the family I'm interested in, I looked at the first page and last page of the section, hoping there might be a date there, but none were found. Where might I find clues as to a more precise date the family was enumerated? I know that 1850 census was also conducted on June 1, 1850, but have seen pages dated September. Was the census taker supposed to enumerate as of June 1st and ignore any births since then and give ages as of June 1st? If so, how well did they typically follow these directions in the 1830 and 1840 censuses?

"The 1850 Census began on 1st June 1850. The enumeration was completed within five months. " - Source: A Guidebook to American Genealogy

This matches what you've observed about the dates on censuses. The data if taken for example 21st September would be relating to the household on 1st June rather than the day it was taken.

**In the same book:**

"The 1830 Census began on 1st June 1830. The enumeration was to be completed within six months but was extended to allow completion within twelve months"

"The 1840 Census began on 1st June 1840. The enumeration was to be completed within nine months but was extended to eighteen months."