| Census Year | Population | % Changea |
| 1790 | 3,929,214 | - |
| 1800 | 5,308,483 | 35.1 |
| 1810 | 7,239,881 | 36.4 |
| 1820 | 9,638,453 | 33.1 |
| 1830 | 12,866,020 | 33.5 |
| 1840 | 17,069,453 | 32.7 |
| 1850 | 23,191,876 | 35.9 |
| 1860 | 31,443,321 | 35.6 |
| 1870 | 39,818,449 | 26.6 |
| 1880 | 50,155,783 | 26.0 |
| 1890 | 62,947,714 | 25.5 |
| 1900 | 75,994,575 | 20.7 |
| 1910 | 91,972,266 | 21.0 |
| 1920 | 105,710,620 | 14.9 |
| 1930 | 122,775,046 | 16.1 |
| 1940 | 131,669,275 | 7.2 |
| 1950 | 151,325,798 | 14.5 |
| 1960 | 179,323,175 | 18.5 |
| 1970 | 203,211,926 | 13.3 |
| 1980 | 226,504,825 | 11.5 |
| 1990 | 249,632,692b | 10.21 |
a. % change from last census.
b. Preliminary figure.
