Only uses the states fully in the Great Plains: N. & S. Dakota, Nebraska, Kansas, Oklahoma
Before states were made, similarly named territories are used.
| Year | N. Dakota | S. Dakota | Oklahoma | Kansas | Nebraska |
| 1860 | | | | 107206 | 28841 |
| 1870 | 2405 | 11776 | | 364399 | 122993 |
| 1880 | 36909 | 98268 | | 996096 | 452402 |
| 1890 | 190983 | 348600 | 258657 | 1428108 | 1062656 |
| 1900 | 319146 | 401570 | 790391 | 1470495 | 1066300 |
| 1910 | 577056 | 583888 | 1657155 | 1690949 | 1192214 |
| 1920 | 646872 | 636547 | 2028283 | 1769257 | 1296372 |
| 1930 | 680845 | 692849 | 2396040 | 1880999 | 1377963 |
| 1940 | 641935 | 642961 | 2336434 | 1801028 | 1315834 |
| 1950 | 619636 | 652740 | 2233351 | 1905299 | 1325510 |
| 1960 | 632446 | 680514 | 2328284 | 2178611 | 1411330 |
| 1970 | 617761 | 665507 | 2559229 | 2246578 | 1483493 |
| 1980 | 652717 | 690768 | 3025290 | 2363679 | 1569825 |
| 1990 | 638800 | 696004 | 3145585 | 2477574 | 1578385 |
| 2000 | 642200 | 754844 | 3450654 | 2688418 | 1711263 |
| 2010 | 672591 | 814180 | 3751351 | 2853118 | 1826341 |
| 2020 | 779094 | 886667 | 3959353 | 2937880 | 1961504 |
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