Population by Community
| City of San Luis | City of Somerton | City of Yuma | Town of Wellton | Yuma County | |
| 2012 Projections | 28,406 | 13,394 | 98,822 | 2,333 | 216,939 |
| 2007 Estimates | 23,007 | 10,835 | 89,040 | 2,120 | 191,581 |
| 2000 Census | 15,322 | 7,266 | 77,515 | 1,829 | 160,026 |
| 1990 Census | 5,646 | 5,295 | 62,141 | 1,227 | 106,895 |
Growth Rates
| City of San Luis | City of Somerton | City of Yuma | Town of Wellton | Yuma County | |
| 2007-2012 | 23.47% | 23.62% | 10.99% | 10.05% | 13.24% |
| 2000-2007 | 50.16% | 49.12% | 14.87% | 15.91% | 19.72% |
| 1990-2000 | 171.38% | 37.22% | 24.74% | 49.06% | 49.70% |
Source: Claritas, 2007 estimates



