The 1840 census was actually taken over a period of a year and a half, beginning on June 1, 1840. Therefore, it contains some records that were taken in that year, but also several records that were taken the following year.
There were several basic questions covered by the 1840 census that were also covered in previous censuses. For example, the 1830 and 1840 censuses recorded the ages of free white males and females in the same way. The age categories began with 5-year increments, which included 0 to 5, 5 to 10, 10 to 15 and15 to 20. Then they increased in 10-year increments until age 100. Finally, there was a category for anyone 100 or older. Town, district, or county of residence was also covered, as were the questions of “free colored persons,” slaves, and aliens.