| | Lannon, WI | Port Washington, WI | United States |
| Population | 1,292 | 12,273 | 329,725,481 |
| Female Population | 44.5% | 52.3% | 50.5% |
| Male Population | 55.5% | 47.7% | 49.5% |
| Median Age | 43.1 | 39 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,109 | 11,290 | 309,327,143 |
| Population - 2000 | 1,009 | 10,467 | 285,036,114 |
| Population - 1990 | 924 | 9,338 | 251,960,433 |
| Pop. 2000 to Now | 27.3% | 15.3% | 15.6% |
| Pop. 1990 to Now | 39.0% | 29.2% | 30.8% |
| space4 | | | |
| Population Density | 522.7 | 2,109.1 | 93.4 |
| Land Area | 2.5 | 5.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lannon, WI | Port Washington, WI | United States |
| Age 0 to 4 | 4.1% | 6.9% | 5.9% |
| Age 5 to 9 | 6.1% | 8.2% | 6.1% |
| Age 10 to 14 | 5.7% | 5.9% | 6.6% |
| Age 15 to 17 | 2.2% | 2.7% | 3.9% |
| Age 18 to 20 | 2.4% | 3.0% | 4.0% |
| Age 21 to 24 | 4.9% | 3.4% | 5.2% |
| Age 25 to 34 | 10.2% | 13.4% | 13.8% |
| Age 35 to 44 | 16.2% | 15.1% | 12.9% |
| Age 45 to 54 | 14.2% | 10.1% | 12.6% |
| Age 55 to 59 | 8.7% | 6.1% | 6.7% |
| Age 60 to 64 | 5.8% | 8.5% | 6.3% |
| Age 65 to 74 | 6.0% | 8.8% | 9.6% |
| Age 75 to 84 | 3.7% | 5.5% | 4.5% |
| Age 85 and over | 9.8% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lannon, WI | Port Washington, WI | United States |
| White | 88.6% | 90.0% | 59.4% |
| Black | 0.0% | 1.7% | 12.2% |
| Asian | 3.9% | 1.8% | 5.6% |
| Native American | 0.3% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.2% | 0.4% |
| Two or More Races | 0.9% | 3.6% | 3.2% |
| Hispanic | 6.2% | 2.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lannon, WI | Port Washington, WI | United States |
| Married Population | 46.4% | 56.0% | 49.8% |
| Currently Married | 46.4% | 55.0% | 48.0% |
| Married but Separated | 0.0% | 1.0% | 1.8% |
| Single Population | 53.6% | 44.0% | 50.2% |
| Never Married | 26.2% | 25.8% | 33.8% |
| Divorced | 13.4% | 13.5% | 10.8% |
| Widowed | 14.0% | 4.7% | 5.6% |
| space5 | | | |
| Household Size | 2.09 | 2.35 | 2.60 |
| Households | 619 | 5,107 | 124,010,992 |
| Family Households | 317 | 3,162 | 80,755,759 |
| Married couple, w/children | 30.9% | 32.7% | 30.5% |
| Married couple, no children | 42.6% | 47.7% | 42.9% |
| Non Family Households | 302 | 1,945 | 43,255,233 |
| Single householder, w/children | 14.2% | 13.1% | 15.8% |
| Single householder, no children | 12.3% | 6.5% | 10.8% |