ZIP Code 21797 has segments in 3 Counties / Independent Cities (Carroll, Howard, Montgomery).
The ZIP Code maps and database are updated 4 times per year.
Database updated: October 1, 2025, Maps updated: May 1, 2024.
POPULATION | |
|---|---|
| Total Population | 9,040 (100%) |
| Population in Households | 9,000 (99.6%) |
| Population in Families | 8,193 (90.6%) |
| Population in Group Quarters1 | 40 ( 0.4%) |
| Population Density | 211 |
| Diversity Index2 | 39 |
INCOME | |
| Median Household Income | $182,998 |
| Average Household Income | $222,690 |
| % of Income for Mortgage4 | 27% |
| Per Capita Income | $77,175 |
| Wealth Index5 | 250 |
| Socioeconomic Status Index6 | Moderate (62.4) |
HOUSING | |
|---|---|
| Total HU (Housing Units) | 3,246 (100%) |
| Owner Occupied HU | 2,892 (89.1%) |
| Renter Occupied HU | 240 ( 7.4%) |
| Vacant Housing Units | 114 ( 3.5%) |
| Median Home Value | $797,000 |
| Average Home Value | $828,028 |
| Housing Affordability Index3 | 85 |
HOUSEHOLDS | |
| Total Households | 3,132 |
| Average Household Size | 2.87 |
| Family Households | 2,563 |
| Average Family Size | 3.00 |
GROWTH RATE / YEAR |
2020-2025 | 2025-2030 |
|---|---|---|
| Population | 0.23% | 0.20% |
| Households | 0.38% | 0.25% |
| Families | 0.26% | |
| Median Household Income | 3.15% | |
| Per Capita Income | 1.99% | |
| Owner Occupied HU | 0.32% |
The table below compares 21797 to the other 458 ZIP Codes in Maryland by rank and percentile using July 1, 2025 data. The location Ranked # 1 has the highest value. A location that ranks higher than 75% of its peers would be in the 75th percentile of the peer group.
| Variable Description | Rank | Percentile |
|---|---|---|
| Total Population | # 190 | 59th |
| Population Density | # 294 | 36th |
| Median Household Income | # 28 | 94th |
| Housing Affordability Index | # 216 | 47th |
| Per Capita Income | # 30 | 94th |
| Diversity Index | # 299 | 35th |
Additional comparisons and rankings can be made with a VERY EASY TO USE Maryland Census Data Comparison Tool.