This database estimates population density (persons per square mile) based on total resident population.  Population density for all years is based on current land area reported by the U.S. Census.

• 1790 population estimates reflect the population on August 2.
• 1800 estimates reflect August 4.
• 1810 estimates reflect August 6.
• 1820 estimates reflect August 7.
• Estimates from 1830-1890 reflect June 1.
• RAND State Statistics estimated population data for individual years from 1790-1890 based on a linear rate of growth between the start and end of each decade.
• Estimates from 1900 to the present reflect the population on July 1 of each year, except 1960, 1970, and 1980, which reflect April 1 estimates.
• U.S. population data for the years 1900 to 1949 exclude the population residing in Alaska and Hawaii.
• National population data for the years 1940 to 1979 cover the resident population plus Armed Forces overseas. For all other years, national population data cover only the resident population only.
• National population data for the years 1900 to 1929 are rounded to the nearest thousand.