Find Datasets & Microdata: Use this page if you need to download data to do detailed analysis using a statistical software package (e.g., R, SPSS, Stata, etc.). Includes data for households and people from Census, ACS, Current Population Survey, etc. as well as international data. Easier-to-use population data for the U.S. is aggregated by geography and can be accessed from the Find U.S. or Find DC Metro Area pages.
Find International Data: Access resources that report country level population data or access points for other countries censuses (useful if you need population data for smaller geographies--below the national level).
Find Economic Census Data: The U.S. Economic Census data is collected every five years. This page accesses recent data as well as historical data about business establishments. Figures include numbers of establishments by geography, industry, information about payroll and more.