Download census data along with GIS boundary files from 1790 to date. Register for a free account to find and download data you then will use with other applications (Excel, GIS apps, statistical software).
ICPSR is a data archive of more than 250,000 files of research in the social and behavioral sciences, hosting specialized collections of data in education, aging, criminal justice, substance abuse, terrorism, and other fields.
Census and survey data for 98 countries as of July, 2020; some data is available for as far back as the 1960s. Register to create a free account thet will allow you to download specific data based on criteria you set and use it in other applications.