| | Seneca, MO | Neosho, MO | United States |
| Population | 2,150 | 12,439 | 329,725,481 |
| Female Population | 48.6% | 50.1% | 50.5% |
| Male Population | 51.4% | 49.9% | 49.5% |
| Median Age | 31.4 | 34.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,339 | 11,850 | 309,327,143 |
| Population - 2000 | 2,135 | 10,505 | 285,036,114 |
| Population - 1990 | 1,885 | 9,254 | 251,960,433 |
| Pop. 2000 to Now | 12.1% | 15.3% | 15.6% |
| Pop. 1990 to Now | 27.0% | 30.9% | 30.8% |
| space4 | | | |
| Population Density | 840.2 | 790.8 | 93.4 |
| Land Area | 2.6 | 15.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Seneca, MO | Neosho, MO | United States |
| Age 0 to 4 | 10.2% | 7.4% | 5.9% |
| Age 5 to 9 | 8.5% | 7.5% | 6.1% |
| Age 10 to 14 | 7.0% | 7.8% | 6.6% |
| Age 15 to 17 | 3.6% | 4.8% | 3.9% |
| Age 18 to 20 | 1.0% | 4.7% | 4.0% |
| Age 21 to 24 | 7.3% | 5.4% | 5.2% |
| Age 25 to 34 | 18.3% | 13.4% | 13.8% |
| Age 35 to 44 | 6.4% | 13.2% | 12.9% |
| Age 45 to 54 | 8.0% | 10.5% | 12.6% |
| Age 55 to 59 | 6.6% | 6.8% | 6.7% |
| Age 60 to 64 | 6.7% | 3.9% | 6.3% |
| Age 65 to 74 | 8.1% | 9.7% | 9.6% |
| Age 75 to 84 | 6.5% | 3.2% | 4.5% |
| Age 85 and over | 1.6% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Seneca, MO | Neosho, MO | United States |
| White | 80.8% | 74.2% | 59.4% |
| Black | 0.0% | 1.8% | 12.2% |
| Asian | 0.7% | 0.4% | 5.6% |
| Native American | 3.9% | 1.2% | 0.6% |
| Hawaiian, Pacific Islander | 5.5% | 2.7% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 6.2% | 7.8% | 3.2% |
| Hispanic | 2.8% | 11.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Seneca, MO | Neosho, MO | United States |
| Married Population | 57.4% | 52.5% | 49.8% |
| Currently Married | 56.2% | 49.8% | 48.0% |
| Married but Separated | 1.2% | 2.6% | 1.8% |
| Single Population | 42.6% | 47.5% | 50.2% |
| Never Married | 19.5% | 27.2% | 33.8% |
| Divorced | 15.2% | 13.6% | 10.8% |
| Widowed | 7.9% | 6.7% | 5.6% |
| space5 | | | |
| Household Size | 3.06 | 2.69 | 2.60 |
| Households | 677 | 4,449 | 124,010,992 |
| Family Households | 502 | 2,860 | 80,755,759 |
| Married couple, w/children | 36.5% | 37.7% | 30.5% |
| Married couple, no children | 36.9% | 39.6% | 42.9% |
| Non Family Households | 175 | 1,589 | 43,255,233 |
| Single householder, w/children | 22.1% | 17.9% | 15.8% |
| Single householder, no children | 4.6% | 4.8% | 10.8% |