ZIP Code 21784 has segments in 2 Counties / Independent Cities (Carroll, Howard).
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 | 41,477 (100%) |
| Population in Households | 40,405 (97.4%) |
| Population in Families | 35,613 (85.9%) |
| Population in Group Quarters1 | 1,072 ( 2.6%) |
| Population Density | 742 |
| Diversity Index2 | 39 |
INCOME | |
| Median Household Income | $149,564 |
| Average Household Income | $179,885 |
| % of Income for Mortgage4 | 23% |
| Per Capita Income | $64,179 |
| Wealth Index5 | 189 |
| Socioeconomic Status Index6 | Moderate (64.1) |
HOUSING | |
|---|---|
| Total HU (Housing Units) | 15,119 (100%) |
| Owner Occupied HU | 12,813 (84.7%) |
| Renter Occupied HU | 1,910 (12.6%) |
| Vacant Housing Units | 396 ( 2.6%) |
| Median Home Value | $543,643 |
| Average Home Value | $578,098 |
| Housing Affordability Index3 | 104 |
HOUSEHOLDS | |
| Total Households | 14,723 |
| Average Household Size | 2.74 |
| Family Households | 11,121 |
| Average Family Size | 3.00 |
GROWTH RATE / YEAR |
2020-2025 | 2025-2030 |
|---|---|---|
| Population | 0.53% | 0.36% |
| Households | 0.66% | 0.51% |
| Families | 0.43% | |
| Median Household Income | 2.51% | |
| Per Capita Income | 1.96% | |
| Owner Occupied HU | 0.74% |
The table below compares 21784 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 | # 40 | 91st |
| Population Density | # 182 | 60th |
| Median Household Income | # 73 | 84th |
| Housing Affordability Index | # 404 | 88th |
| Per Capita Income | # 99 | 79th |
| Diversity Index | # 297 | 35th |
Additional comparisons and rankings can be made with a VERY EASY TO USE Maryland Census Data Comparison Tool.