| | Sunnyside, WA | Leavenworth, WA | United States |
| Population | 16,343 | 2,395 | 329,725,481 |
| Female Population | 49.6% | 52.8% | 50.5% |
| Male Population | 50.4% | 47.2% | 49.5% |
| Median Age | 26.5 | 40.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 15,986 | 1,979 | 309,327,143 |
| Population - 2000 | 13,905 | 2,074 | 285,036,114 |
| Population - 1990 | 11,238 | 1,692 | 251,960,433 |
| Pop. 2000 to Now | 21.7% | 13.2% | 15.6% |
| Pop. 1990 to Now | 50.6% | 38.8% | 30.8% |
| space4 | | | |
| Population Density | 2,175.6 | 1,804.8 | 93.4 |
| Land Area | 7.5 | 1.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Sunnyside, WA | Leavenworth, WA | United States |
| Age 0 to 4 | 9.8% | 5.2% | 5.9% |
| Age 5 to 9 | 12.3% | 6.6% | 6.1% |
| Age 10 to 14 | 12.6% | 6.7% | 6.6% |
| Age 15 to 17 | 5.3% | 5.0% | 3.9% |
| Age 18 to 20 | 3.9% | 2.2% | 4.0% |
| Age 21 to 24 | 4.5% | 4.1% | 5.2% |
| Age 25 to 34 | 14.9% | 10.3% | 13.8% |
| Age 35 to 44 | 10.8% | 17.5% | 12.9% |
| Age 45 to 54 | 8.8% | 11.8% | 12.6% |
| Age 55 to 59 | 4.4% | 9.6% | 6.7% |
| Age 60 to 64 | 3.3% | 6.9% | 6.3% |
| Age 65 to 74 | 5.1% | 7.2% | 9.6% |
| Age 75 to 84 | 1.9% | 3.6% | 4.5% |
| Age 85 and over | 2.4% | 3.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sunnyside, WA | Leavenworth, WA | United States |
| White | 13.5% | 86.7% | 59.4% |
| Black | 0.0% | 0.7% | 12.2% |
| Asian | 0.0% | 1.8% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.3% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 3.2% | 3.2% |
| Hispanic | 86.2% | 7.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sunnyside, WA | Leavenworth, WA | United States |
| Married Population | 48.6% | 52.4% | 49.8% |
| Currently Married | 46.0% | 50.2% | 48.0% |
| Married but Separated | 2.7% | 2.2% | 1.8% |
| Single Population | 51.4% | 47.6% | 50.2% |
| Never Married | 36.6% | 28.8% | 33.8% |
| Divorced | 8.4% | 13.8% | 10.8% |
| Widowed | 6.3% | 5.0% | 5.6% |
| space5 | | | |
| Household Size | 3.81 | 2.22 | 2.60 |
| Households | 4,225 | 1,081 | 124,010,992 |
| Family Households | 3,325 | 595 | 80,755,759 |
| Married couple, w/children | 35.3% | 33.1% | 30.5% |
| Married couple, no children | 24.3% | 46.1% | 42.9% |
| Non Family Households | 900 | 486 | 43,255,233 |
| Single householder, w/children | 32.3% | 19.2% | 15.8% |
| Single householder, no children | 8.1% | 1.7% | 10.8% |