| | Clay Center, KS | Lyons, KS | United States |
| Population | 4,147 | 3,580 | 329,725,481 |
| Female Population | 51.4% | 49.5% | 50.5% |
| Male Population | 48.6% | 50.5% | 49.5% |
| Median Age | 41.3 | 39.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,348 | 3,746 | 309,327,143 |
| Population - 2000 | 4,564 | 3,732 | 285,036,114 |
| Population - 1990 | 4,613 | 3,688 | 251,960,433 |
| Pop. 2000 to Now | -12.6% | -8.0% | 15.6% |
| Pop. 1990 to Now | -13.5% | -6.9% | 30.8% |
| space4 | | | |
| Population Density | 1,303.3 | 1,384.9 | 93.4 |
| Land Area | 3.2 | 2.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Clay Center, KS | Lyons, KS | United States |
| Age 0 to 4 | 6.6% | 6.3% | 5.9% |
| Age 5 to 9 | 7.5% | 7.2% | 6.1% |
| Age 10 to 14 | 9.1% | 5.0% | 6.6% |
| Age 15 to 17 | 1.9% | 3.0% | 3.9% |
| Age 18 to 20 | 0.0% | 2.9% | 4.0% |
| Age 21 to 24 | 6.1% | 7.1% | 5.2% |
| Age 25 to 34 | 9.6% | 13.5% | 13.8% |
| Age 35 to 44 | 11.7% | 13.7% | 12.9% |
| Age 45 to 54 | 9.7% | 10.5% | 12.6% |
| Age 55 to 59 | 2.1% | 6.6% | 6.7% |
| Age 60 to 64 | 8.4% | 6.2% | 6.3% |
| Age 65 to 74 | 14.3% | 10.0% | 9.6% |
| Age 75 to 84 | 6.7% | 4.3% | 4.5% |
| Age 85 and over | 6.4% | 3.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Clay Center, KS | Lyons, KS | United States |
| White | 95.4% | 74.9% | 59.4% |
| Black | 3.1% | 2.3% | 12.2% |
| Asian | 0.5% | 0.6% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 2.6% | 0.4% |
| Two or More Races | 0.0% | 3.2% | 3.2% |
| Hispanic | 1.0% | 16.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Clay Center, KS | Lyons, KS | United States |
| Married Population | 53.2% | 55.2% | 49.8% |
| Currently Married | 52.6% | 55.2% | 48.0% |
| Married but Separated | 0.6% | 0.0% | 1.8% |
| Single Population | 46.8% | 44.8% | 50.2% |
| Never Married | 20.7% | 23.9% | 33.8% |
| Divorced | 11.9% | 12.8% | 10.8% |
| Widowed | 14.1% | 8.2% | 5.6% |
| space5 | | | |
| Household Size | 2.13 | 2.20 | 2.60 |
| Households | 1,903 | 1,575 | 124,010,992 |
| Family Households | 1,059 | 971 | 80,755,759 |
| Married couple, w/children | 30.3% | 38.6% | 30.5% |
| Married couple, no children | 43.7% | 43.7% | 42.9% |
| Non Family Households | 844 | 604 | 43,255,233 |
| Single householder, w/children | 16.6% | 12.7% | 15.8% |
| Single householder, no children | 9.3% | 5.0% | 10.8% |