census records

divided into 4 time periods:
Early census years (1790-1840) = citizenship, occupation, disability, education
mid 19th century (1850-1870) = where born, school, occupation, property
late 19th century (1880-1890) = ages, marital status, where they were born and where their parents were born
20th century (1900-1930) = all the birth dates of the household, where they and their parents were born, if they own their home, immigration/naturalization

visit: lesson 1: the federal census:an historical overview
note (to view the video, you need to be in firefox)

What information was collected about the people in different census time periods?  It might provide new clues to research.

Census records are available to view 72 years after a census was taken.  (This provides privacy for living individuals.)  The 1950 census will be released April 1, 2022.

Most of the 1890 census' population schedules were badly damaged by a fire in the Commerce Department Building in January 1921.  The records of only 6,160 of the 62,979,766 people enumerated survived the fire.
The original 1890 census enumerated people differently than ever before that time. Each family was enumerated on a separate sheet of paper. 1890 was the only year this was done.

Hints: start with what you know and work back in time.  That way you start with more accurate information to guide you in the right direction for your research.