| | Seneca, KS | Shawnee, KS | United States |
| Population | 2,029 | 67,021 | 329,725,481 |
| Female Population | 47.7% | 51.5% | 50.5% |
| Male Population | 52.3% | 48.5% | 49.5% |
| Median Age | 44.7 | 37.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,002 | 62,316 | 309,327,143 |
| Population - 2000 | 2,122 | 47,996 | 285,036,114 |
| Population - 1990 | 2,027 | 37,993 | 251,960,433 |
| Pop. 2000 to Now | -2.0% | 38.1% | 15.6% |
| Pop. 1990 to Now | 2.6% | 74.5% | 30.8% |
| space4 | | | |
| Population Density | 1,227.5 | 1,596.7 | 93.4 |
| Land Area | 1.7 | 42.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Seneca, KS | Shawnee, KS | United States |
| Age 0 to 4 | 3.9% | 6.4% | 5.9% |
| Age 5 to 9 | 9.7% | 8.1% | 6.1% |
| Age 10 to 14 | 6.6% | 6.4% | 6.6% |
| Age 15 to 17 | 3.2% | 4.4% | 3.9% |
| Age 18 to 20 | 1.7% | 3.5% | 4.0% |
| Age 21 to 24 | 3.6% | 5.0% | 5.2% |
| Age 25 to 34 | 12.7% | 12.8% | 13.8% |
| Age 35 to 44 | 9.2% | 14.0% | 12.9% |
| Age 45 to 54 | 8.4% | 14.1% | 12.6% |
| Age 55 to 59 | 7.9% | 6.0% | 6.7% |
| Age 60 to 64 | 7.5% | 5.5% | 6.3% |
| Age 65 to 74 | 10.0% | 8.8% | 9.6% |
| Age 75 to 84 | 8.3% | 3.4% | 4.5% |
| Age 85 and over | 7.3% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Seneca, KS | Shawnee, KS | United States |
| White | 92.0% | 80.8% | 59.4% |
| Black | 0.7% | 4.9% | 12.2% |
| Asian | 0.0% | 3.4% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.4% | 2.9% | 3.2% |
| Hispanic | 5.7% | 7.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Seneca, KS | Shawnee, KS | United States |
| Married Population | 61.0% | 60.6% | 49.8% |
| Currently Married | 60.3% | 59.8% | 48.0% |
| Married but Separated | 0.7% | 0.8% | 1.8% |
| Single Population | 39.0% | 39.4% | 50.2% |
| Never Married | 19.3% | 27.3% | 33.8% |
| Divorced | 7.4% | 8.9% | 10.8% |
| Widowed | 12.3% | 3.2% | 5.6% |
| space5 | | | |
| Household Size | 2.23 | 2.66 | 2.60 |
| Households | 857 | 25,027 | 124,010,992 |
| Family Households | 556 | 17,829 | 80,755,759 |
| Married couple, w/children | 29.9% | 38.6% | 30.5% |
| Married couple, no children | 59.5% | 46.8% | 42.9% |
| Non Family Households | 301 | 7,198 | 43,255,233 |
| Single householder, w/children | 7.4% | 9.5% | 15.8% |
| Single householder, no children | 3.2% | 5.1% | 10.8% |