| | Rigby, ID | Dillon, MT | United States |
| Population | 4,920 | 3,930 | 329,725,481 |
| Female Population | 49.7% | 50.5% | 50.5% |
| Male Population | 50.3% | 49.5% | 49.5% |
| Median Age | 27.3 | 28.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,944 | 4,153 | 309,327,143 |
| Population - 2000 | 2,998 | 3,752 | 285,036,114 |
| Population - 1990 | 2,681 | 3,991 | 251,960,433 |
| Pop. 2000 to Now | 47.8% | 15.5% | 15.6% |
| Pop. 1990 to Now | 65.2% | 8.6% | 30.8% |
| space4 | | | |
| Population Density | 2,088.3 | 2,215.3 | 93.4 |
| Land Area | 2.4 | 1.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Rigby, ID | Dillon, MT | United States |
| Age 0 to 4 | 15.1% | 3.5% | 5.9% |
| Age 5 to 9 | 8.6% | 5.6% | 6.1% |
| Age 10 to 14 | 7.4% | 4.2% | 6.6% |
| Age 15 to 17 | 1.7% | 4.6% | 3.9% |
| Age 18 to 20 | 0.7% | 12.8% | 4.0% |
| Age 21 to 24 | 8.3% | 14.7% | 5.2% |
| Age 25 to 34 | 22.9% | 13.1% | 13.8% |
| Age 35 to 44 | 9.5% | 9.4% | 12.9% |
| Age 45 to 54 | 10.4% | 6.0% | 12.6% |
| Age 55 to 59 | 3.4% | 4.0% | 6.7% |
| Age 60 to 64 | 1.9% | 6.1% | 6.3% |
| Age 65 to 74 | 5.3% | 9.5% | 9.6% |
| Age 75 to 84 | 3.1% | 4.1% | 4.5% |
| Age 85 and over | 1.7% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Rigby, ID | Dillon, MT | United States |
| White | 81.3% | 89.5% | 59.4% |
| Black | 0.0% | 2.2% | 12.2% |
| Asian | 1.5% | 0.2% | 5.6% |
| Native American | 3.8% | 2.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.5% | 3.1% | 3.2% |
| Hispanic | 11.9% | 2.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Rigby, ID | Dillon, MT | United States |
| Married Population | 72.9% | 37.5% | 49.8% |
| Currently Married | 70.1% | 37.5% | 48.0% |
| Married but Separated | 2.9% | 0.0% | 1.8% |
| Single Population | 27.1% | 62.5% | 50.2% |
| Never Married | 11.6% | 46.9% | 33.8% |
| Divorced | 10.3% | 12.5% | 10.8% |
| Widowed | 5.1% | 3.1% | 5.6% |
| space5 | | | |
| Household Size | 2.70 | 2.24 | 2.60 |
| Households | 1,808 | 1,532 | 124,010,992 |
| Family Households | 1,320 | 745 | 80,755,759 |
| Married couple, w/children | 48.3% | 32.9% | 30.5% |
| Married couple, no children | 40.5% | 49.0% | 42.9% |
| Non Family Households | 488 | 787 | 43,255,233 |
| Single householder, w/children | 8.9% | 13.2% | 15.8% |
| Single householder, no children | 2.3% | 5.0% | 10.8% |