St. Mary's County MD Information


St. Mary's County Subdivisions

St. Mary's County MD Data & Demographics (As of July 1, 2016)


Total Population 115,458
Population in Households 112,597
Population in Familes 94,493
Population in Group Qrtrs 2,861
Population Density1 323
Diversity Index2 44


Total Households 41,020
Average Household Size 2.74
Family Households 29,333
Average Family Size 3


Total Housing Units 45,390 (100%)
Owner Occupied HU 28,657 (63.1%)
Renter Occupied HU 12,363 (27.2%)
Vacant Housing Units 4,370 ( 9.6%)
Median Home Value $313,399
Average Home Value $365,486


Median Household Income $83,941
Average Household Income $99,515
Per Capita Income $36,227
  (Compound Annual Growth Rates)


2010-2015 2015-2020
Population 1.51% 1.47%
Households 1.4% 1.4%
Families 1.28% 1.32%
Median Household Income   1.88%
Per Capita Income   1.58%
1) Population Density = Total Population per square mile.
2) The Diversity Index is a scale of 0 to 100 that represents the likelyhood 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.
Based on Census 2010 counts, the Diversity Index for the United States was 60.6 and it is expected to increase to 64.8 by July 1, 2018.


St. Mary's County MD - Peer Comparisons by Rank and Percentile

The table below compares St. Mary's County to the other 24 counties / independent cities and county equivalents in Maryland by rank and percentile using July 1, 2016 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 # 12 54th
Population Density1 # 13 50th
Diversity Index2 # 13 50th
Median Household Income # 9 67th
Per Capita Income # 10 63rd

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