| | Lincoln, IL | Mason City, IL | United States |
| Population | 13,217 | 2,205 | 329,725,481 |
| Female Population | 49.2% | 53.8% | 50.5% |
| Male Population | 50.8% | 46.2% | 49.5% |
| Median Age | 39.1 | 47 | 38.4 |
| space3 | | | |
| Population - 2010 | 14,532 | 2,339 | 309,327,143 |
| Population - 2000 | 15,369 | 2,558 | 285,036,114 |
| Population - 1990 | 15,418 | 2,323 | 251,960,433 |
| Pop. 2000 to Now | -12.8% | -18.4% | 15.6% |
| Pop. 1990 to Now | -13.1% | -10.1% | 30.8% |
| space4 | | | |
| Population Density | 2,114.4 | 2,174.6 | 93.4 |
| Land Area | 6.3 | 1.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lincoln, IL | Mason City, IL | United States |
| Age 0 to 4 | 5.7% | 5.4% | 5.9% |
| Age 5 to 9 | 4.2% | 5.1% | 6.1% |
| Age 10 to 14 | 4.9% | 4.9% | 6.6% |
| Age 15 to 17 | 3.5% | 3.7% | 3.9% |
| Age 18 to 20 | 8.0% | 4.8% | 4.0% |
| Age 21 to 24 | 6.9% | 4.5% | 5.2% |
| Age 25 to 34 | 12.3% | 10.6% | 13.8% |
| Age 35 to 44 | 9.4% | 9.4% | 12.9% |
| Age 45 to 54 | 10.7% | 9.3% | 12.6% |
| Age 55 to 59 | 6.6% | 8.8% | 6.7% |
| Age 60 to 64 | 6.4% | 9.0% | 6.3% |
| Age 65 to 74 | 11.9% | 14.5% | 9.6% |
| Age 75 to 84 | 4.7% | 6.3% | 4.5% |
| Age 85 and over | 4.9% | 3.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lincoln, IL | Mason City, IL | United States |
| White | 86.8% | 98.1% | 59.4% |
| Black | 5.4% | 0.5% | 12.2% |
| Asian | 0.9% | 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 | 4.0% | 0.2% | 3.2% |
| Hispanic | 2.8% | 1.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lincoln, IL | Mason City, IL | United States |
| Married Population | 45.2% | 50.4% | 49.8% |
| Currently Married | 44.2% | 48.3% | 48.0% |
| Married but Separated | 0.9% | 2.1% | 1.8% |
| Single Population | 54.8% | 49.6% | 50.2% |
| Never Married | 34.5% | 27.9% | 33.8% |
| Divorced | 12.2% | 10.2% | 10.8% |
| Widowed | 8.1% | 11.5% | 5.6% |
| space5 | | | |
| Household Size | 2.08 | 2.17 | 2.60 |
| Households | 5,773 | 983 | 124,010,992 |
| Family Households | 3,288 | 575 | 80,755,759 |
| Married couple, w/children | 22.4% | 28.5% | 30.5% |
| Married couple, no children | 50.1% | 47.8% | 42.9% |
| Non Family Households | 2,485 | 408 | 43,255,233 |
| Single householder, w/children | 16.8% | 16.9% | 15.8% |
| Single householder, no children | 10.7% | 6.8% | 10.8% |