| | Gilbert, IA | Lamar, MO | United States |
| Population | 1,082 | 4,317 | 329,725,481 |
| Female Population | 50.2% | 52.6% | 50.5% |
| Male Population | 49.8% | 47.4% | 49.5% |
| Median Age | 43.3 | 38.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,080 | 4,531 | 309,327,143 |
| Population - 2000 | 987 | 4,425 | 285,036,114 |
| Population - 1990 | 796 | 4,168 | 251,960,433 |
| Pop. 2000 to Now | 16.7% | -4.3% | 15.6% |
| Pop. 1990 to Now | 44.7% | 1.6% | 30.8% |
| space4 | | | |
| Population Density | 1,101.8 | 843.8 | 93.4 |
| Land Area | 1.0 | 5.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gilbert, IA | Lamar, MO | United States |
| Age 0 to 4 | 4.2% | 5.1% | 5.9% |
| Age 5 to 9 | 6.8% | 3.7% | 6.1% |
| Age 10 to 14 | 6.9% | 7.4% | 6.6% |
| Age 15 to 17 | 6.8% | 5.3% | 3.9% |
| Age 18 to 20 | 1.8% | 3.8% | 4.0% |
| Age 21 to 24 | 3.6% | 8.1% | 5.2% |
| Age 25 to 34 | 12.0% | 11.6% | 13.8% |
| Age 35 to 44 | 10.6% | 13.3% | 12.9% |
| Age 45 to 54 | 17.8% | 11.5% | 12.6% |
| Age 55 to 59 | 9.0% | 5.7% | 6.7% |
| Age 60 to 64 | 5.5% | 7.6% | 6.3% |
| Age 65 to 74 | 11.5% | 10.8% | 9.6% |
| Age 75 to 84 | 2.8% | 4.4% | 4.5% |
| Age 85 and over | 0.7% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gilbert, IA | Lamar, MO | United States |
| White | 88.4% | 93.7% | 59.4% |
| Black | 0.3% | 0.3% | 12.2% |
| Asian | 0.8% | 0.0% | 5.6% |
| Native American | 3.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.7% | 0.4% | 0.4% |
| Two or More Races | 3.9% | 3.5% | 3.2% |
| Hispanic | 3.0% | 2.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gilbert, IA | Lamar, MO | United States |
| Married Population | 70.2% | 46.5% | 49.8% |
| Currently Married | 70.2% | 42.9% | 48.0% |
| Married but Separated | 0.0% | 3.6% | 1.8% |
| Single Population | 29.8% | 53.5% | 50.2% |
| Never Married | 19.5% | 30.8% | 33.8% |
| Divorced | 5.7% | 10.5% | 10.8% |
| Widowed | 4.6% | 12.2% | 5.6% |
| space5 | | | |
| Household Size | 2.37 | 2.37 | 2.60 |
| Households | 456 | 1,760 | 124,010,992 |
| Family Households | 357 | 1,107 | 80,755,759 |
| Married couple, w/children | 40.1% | 19.1% | 30.5% |
| Married couple, no children | 51.0% | 36.4% | 42.9% |
| Non Family Households | 99 | 653 | 43,255,233 |
| Single householder, w/children | 4.5% | 32.0% | 15.8% |
| Single householder, no children | 4.5% | 12.6% | 10.8% |