Rockville, MD 20851 ZIP Code Profile

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Rockville, MD

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ZIP Code 20851: Basic Data & USPS Preferred City Name

Preferred Name, USPS
Rockville, MD 20851

  • ZIP Code Type: STANDARD
  • Businesses Addresses: 117
  • Single Family Addresses: 3,754
  • Multi-Family Addresses: 1,322
  • County: Montgomery County
  • Centroid: Latitude 39.077, Longitude -77.126
  • Time Zone: Eastern Time Zone (UTC -5 hours)
  • Observes DST: Yes

Neighborhood Data

Address Based Hyperlocal Data Input an address and get data & demographics for the pertinent census block group (CBG), a searchable map and a customized directory. The CBG is the smallest geographical unit used by the Census Bureau for reporting certain data.


20851 ZIP Code Map

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Rockville, MD 20851 Data & Demographics (As of July 1, 2017)


Total Population 15,532
Daytime Population: Workers 3,340
Daytime Population: Residents 6,581
Total Daytime Population (TDP) 9,921
Ratio TDP/Total Population1 0.64
Population in Households 15,380
Population in Familes 11,964
Population in Group Qrtrs 152
Population Density2 6,693
Diversity Index3 86


Median Household Income $86,234
Average Household Income $101,782
Per Capita Income $34,623


Total Housing Units 5,584 (100%)
Owner Occupied HU 3,072 (55.0%)
Renter Occupied HU 2,157 (38.6%)
Vacant Housing Units 355 ( 6.4%)
Median Home Value $354,454
Average Home Value $373,503


Total Households 5,229
Average Household Size 2.94
Family Households 3,555
Average Family Size 3
  1. If the ratio of the TDP to Total Population is greater than 1, the location gains population during the day when commuting workers are present. If the ratio is less than 1, the location is more of a bedroom community where people commute to another place for work.
  2. Population Density = Total Population per square mile.
  3. The Diversity Index is a scale of 0 to 100 that represents the likelihood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.
  (Compound Annual Growth Rates)


2010-2015 2015-2020
Population 1.22% 1.19%
Households 1.04% 1.15%
Families 0.91% 1.04%
Median Household Income   1.4%
Per Capita Income   2.33%

Rockville, MD 20851 - Peer Comparisons by Rank and Percentile

The table below compares 20851 to the other 456 ZIP Codes in Maryland by rank and percentile using July 1, 2017 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 # 147 68th
Population Density # 29 94th
Diversity Index # 10 98th
Median Household Income # 181 61st
Per Capita Income # 244 47th

Additional comparisons and rankings can be made with a VERY EASY TO USE Maryland Census Data Comparison Tool.

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