| | St. Francis, KS | Protection, KS | United States |
| Population | 1,331 | 448 | 329,725,481 |
| Female Population | 58.5% | 48.9% | 50.5% |
| Male Population | 41.6% | 51.1% | 49.5% |
| Median Age | 48.7 | 45.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,323 | 513 | 309,327,143 |
| Population - 2000 | 1,497 | 558 | 285,036,114 |
| Population - 1990 | 1,495 | 625 | 251,960,433 |
| Pop. 2000 to Now | -15.4% | -17.6% | 15.6% |
| Pop. 1990 to Now | -15.3% | -26.4% | 30.8% |
| space4 | | | |
| Population Density | 1,553.1 | 483.3 | 93.4 |
| Land Area | 0.9 | 0.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | St. Francis, KS | Protection, KS | United States |
| Age 0 to 4 | 6.3% | 4.7% | 5.9% |
| Age 5 to 9 | 6.7% | 2.9% | 6.1% |
| Age 10 to 14 | 4.4% | 6.3% | 6.6% |
| Age 15 to 17 | 3.5% | 2.7% | 3.9% |
| Age 18 to 20 | 4.3% | 3.1% | 4.0% |
| Age 21 to 24 | 3.0% | 3.8% | 5.2% |
| Age 25 to 34 | 10.4% | 2.0% | 13.8% |
| Age 35 to 44 | 8.6% | 22.3% | 12.9% |
| Age 45 to 54 | 4.5% | 11.2% | 12.6% |
| Age 55 to 59 | 8.0% | 8.5% | 6.7% |
| Age 60 to 64 | 7.2% | 8.3% | 6.3% |
| Age 65 to 74 | 15.4% | 10.5% | 9.6% |
| Age 75 to 84 | 11.6% | 10.7% | 4.5% |
| Age 85 and over | 6.2% | 3.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | St. Francis, KS | Protection, KS | United States |
| White | 89.9% | 92.9% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.5% | 0.4% | 3.2% |
| Hispanic | 8.6% | 6.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | St. Francis, KS | Protection, KS | United States |
| Married Population | 47.8% | 45.1% | 49.8% |
| Currently Married | 47.5% | 45.1% | 48.0% |
| Married but Separated | 0.4% | 0.0% | 1.8% |
| Single Population | 52.2% | 54.9% | 50.2% |
| Never Married | 22.6% | 29.8% | 33.8% |
| Divorced | 14.5% | 12.2% | 10.8% |
| Widowed | 15.1% | 13.0% | 5.6% |
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| Household Size | 2.07 | 1.96 | 2.60 |
| Households | 624 | 207 | 124,010,992 |
| Family Households | 279 | 120 | 80,755,759 |
| Married couple, w/children | 25.1% | 30.0% | 30.5% |
| Married couple, no children | 45.5% | 53.3% | 42.9% |
| Non Family Households | 345 | 87 | 43,255,233 |
| Single householder, w/children | 22.2% | 10.0% | 15.8% |
| Single householder, no children | 7.2% | 6.7% | 10.8% |