| | Gurnee, IL | Gary, IN | United States |
| Population | 30,826 | 69,739 | 329,725,481 |
| Female Population | 52.9% | 54.2% | 50.5% |
| Male Population | 47.1% | 45.8% | 49.5% |
| Median Age | 40 | 37.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 31,256 | 80,159 | 309,327,143 |
| Population - 2000 | 28,834 | 102,746 | 285,036,114 |
| Population - 1990 | 13,701 | 116,646 | 251,960,433 |
| Pop. 2000 to Now | 4.6% | -27.3% | 15.6% |
| Pop. 1990 to Now | 120.2% | -36.0% | 30.8% |
| space4 | | | |
| Population Density | 2,282.9 | 1,402.7 | 93.4 |
| Land Area | 13.5 | 49.7 | 3,531,905.4 |
| Water Area | 0.1 | 7.5 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gurnee, IL | Gary, IN | United States |
| Age 0 to 4 | 4.1% | 7.1% | 5.9% |
| Age 5 to 9 | 7.1% | 7.8% | 6.1% |
| Age 10 to 14 | 5.8% | 7.8% | 6.6% |
| Age 15 to 17 | 4.7% | 4.5% | 3.9% |
| Age 18 to 20 | 5.6% | 3.9% | 4.0% |
| Age 21 to 24 | 5.6% | 4.4% | 5.2% |
| Age 25 to 34 | 11.2% | 11.6% | 13.8% |
| Age 35 to 44 | 12.2% | 11.7% | 12.9% |
| Age 45 to 54 | 16.8% | 10.2% | 12.6% |
| Age 55 to 59 | 7.6% | 6.1% | 6.7% |
| Age 60 to 64 | 6.8% | 6.3% | 6.3% |
| Age 65 to 74 | 7.9% | 11.5% | 9.6% |
| Age 75 to 84 | 3.3% | 4.9% | 4.5% |
| Age 85 and over | 1.3% | 2.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gurnee, IL | Gary, IN | United States |
| White | 61.5% | 9.9% | 59.4% |
| Black | 7.1% | 77.9% | 12.2% |
| Asian | 12.5% | 0.3% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.4% | 0.4% |
| Two or More Races | 3.2% | 2.8% | 3.2% |
| Hispanic | 15.4% | 8.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gurnee, IL | Gary, IN | United States |
| Married Population | 55.1% | 29.6% | 49.8% |
| Currently Married | 54.3% | 26.0% | 48.0% |
| Married but Separated | 0.8% | 3.5% | 1.8% |
| Single Population | 44.9% | 70.4% | 50.2% |
| Never Married | 32.5% | 46.7% | 33.8% |
| Divorced | 7.7% | 15.0% | 10.8% |
| Widowed | 4.7% | 8.7% | 5.6% |
| space5 | | | |
| Household Size | 2.65 | 2.49 | 2.60 |
| Households | 11,630 | 27,773 | 124,010,992 |
| Family Households | 8,134 | 16,519 | 80,755,759 |
| Married couple, w/children | 36.3% | 10.4% | 30.5% |
| Married couple, no children | 45.7% | 26.8% | 42.9% |
| Non Family Households | 3,496 | 11,254 | 43,255,233 |
| Single householder, w/children | 10.1% | 41.2% | 15.8% |
| Single householder, no children | 7.9% | 21.6% | 10.8% |