| | Lamar, AR | Clarksville, AR | United States |
| Population | 1,535 | 9,444 | 329,725,481 |
| Female Population | 53.0% | 46.4% | 50.5% |
| Male Population | 47.0% | 53.6% | 49.5% |
| Median Age | 32.2 | 34.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,618 | 9,201 | 309,327,143 |
| Population - 2000 | 1,415 | 7,719 | 285,036,114 |
| Population - 1990 | 768 | 5,833 | 251,960,433 |
| Pop. 2000 to Now | 22.2% | 25.9% | 15.6% |
| Pop. 1990 to Now | 125.1% | 66.7% | 30.8% |
| space4 | | | |
| Population Density | 332.6 | 510.3 | 93.4 |
| Land Area | 4.6 | 18.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lamar, AR | Clarksville, AR | United States |
| Age 0 to 4 | 7.6% | 6.4% | 5.9% |
| Age 5 to 9 | 8.5% | 5.6% | 6.1% |
| Age 10 to 14 | 7.5% | 5.4% | 6.6% |
| Age 15 to 17 | 6.3% | 3.9% | 3.9% |
| Age 18 to 20 | 2.5% | 6.9% | 4.0% |
| Age 21 to 24 | 5.1% | 9.4% | 5.2% |
| Age 25 to 34 | 16.7% | 13.7% | 13.8% |
| Age 35 to 44 | 10.4% | 7.9% | 12.9% |
| Age 45 to 54 | 6.3% | 11.1% | 12.6% |
| Age 55 to 59 | 4.0% | 7.9% | 6.7% |
| Age 60 to 64 | 3.8% | 4.9% | 6.3% |
| Age 65 to 74 | 13.2% | 8.8% | 9.6% |
| Age 75 to 84 | 5.5% | 6.5% | 4.5% |
| Age 85 and over | 2.7% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lamar, AR | Clarksville, AR | United States |
| White | 82.8% | 60.7% | 59.4% |
| Black | 1.6% | 3.9% | 12.2% |
| Asian | 0.1% | 5.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.9% | 0.4% |
| Two or More Races | 7.4% | 4.0% | 3.2% |
| Hispanic | 8.1% | 25.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lamar, AR | Clarksville, AR | United States |
| Married Population | 57.9% | 42.3% | 49.8% |
| Currently Married | 55.8% | 39.6% | 48.0% |
| Married but Separated | 2.1% | 2.7% | 1.8% |
| Single Population | 42.1% | 57.7% | 50.2% |
| Never Married | 19.9% | 35.6% | 33.8% |
| Divorced | 12.9% | 17.4% | 10.8% |
| Widowed | 9.2% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.60 | 2.37 | 2.60 |
| Households | 581 | 3,691 | 124,010,992 |
| Family Households | 397 | 2,148 | 80,755,759 |
| Married couple, w/children | 42.6% | 22.3% | 30.5% |
| Married couple, no children | 38.5% | 44.7% | 42.9% |
| Non Family Households | 184 | 1,543 | 43,255,233 |
| Single householder, w/children | 15.4% | 23.6% | 15.8% |
| Single householder, no children | 3.5% | 9.4% | 10.8% |