| | Klamath, CA | Lincoln, CA | United States |
| Population | 946 | 49,203 | 329,725,481 |
| Female Population | 53.7% | 52.0% | 50.5% |
| Male Population | 46.3% | 48.0% | 49.5% |
| Median Age | 48.9 | 43.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 893 | 43,094 | 309,327,143 |
| Population - 2000 | 651 | 11,205 | 285,036,114 |
| Population - 1990 | 827 | 7,248 | 251,960,433 |
| Pop. 2000 to Now | 14.0% | 337.3% | 15.6% |
| Pop. 1990 to Now | -10.3% | 576.0% | 30.8% |
| space4 | | | |
| Population Density | 76.3 | 2,092.9 | 93.4 |
| Land Area | 12.4 | 23.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Klamath, CA | Lincoln, CA | United States |
| Age 0 to 4 | 5.1% | 5.6% | 5.9% |
| Age 5 to 9 | 7.6% | 7.8% | 6.1% |
| Age 10 to 14 | 7.0% | 6.1% | 6.6% |
| Age 15 to 17 | 5.4% | 3.8% | 3.9% |
| Age 18 to 20 | 1.8% | 2.1% | 4.0% |
| Age 21 to 24 | 2.9% | 3.2% | 5.2% |
| Age 25 to 34 | 8.0% | 10.4% | 13.8% |
| Age 35 to 44 | 10.1% | 12.3% | 12.9% |
| Age 45 to 54 | 12.8% | 11.4% | 12.6% |
| Age 55 to 59 | 5.0% | 4.8% | 6.7% |
| Age 60 to 64 | 8.1% | 5.7% | 6.3% |
| Age 65 to 74 | 11.7% | 13.4% | 9.6% |
| Age 75 to 84 | 12.4% | 9.9% | 4.5% |
| Age 85 and over | 2.1% | 3.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Klamath, CA | Lincoln, CA | United States |
| White | 49.9% | 69.2% | 59.4% |
| Black | 0.0% | 1.0% | 12.2% |
| Asian | 0.2% | 6.6% | 5.6% |
| Native American | 32.3% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 3.3% | 3.7% | 3.2% |
| Hispanic | 14.3% | 18.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Klamath, CA | Lincoln, CA | United States |
| Married Population | 47.4% | 62.0% | 49.8% |
| Currently Married | 44.5% | 60.9% | 48.0% |
| Married but Separated | 2.9% | 1.2% | 1.8% |
| Single Population | 52.6% | 38.0% | 50.2% |
| Never Married | 22.8% | 21.1% | 33.8% |
| Divorced | 15.4% | 9.5% | 10.8% |
| Widowed | 14.5% | 7.5% | 5.6% |
| space5 | | | |
| Household Size | 2.67 | 2.63 | 2.60 |
| Households | 352 | 18,619 | 124,010,992 |
| Family Households | 240 | 13,653 | 80,755,759 |
| Married couple, w/children | 20.0% | 32.7% | 30.5% |
| Married couple, no children | 43.3% | 51.1% | 42.9% |
| Non Family Households | 112 | 4,966 | 43,255,233 |
| Single householder, w/children | 25.0% | 9.3% | 15.8% |
| Single householder, no children | 11.7% | 6.9% | 10.8% |