San Mar, MD Profile: Facts & Data

The primary coordinate point for San Mar is located at latitude 39.5509 and longitude -77.6444 in Washington County. The formal boundaries for the San Mar Census Designated Place encompass a land area of 0.45 sq. miles and a water area of 0 sq. miles. Washington County is in the Eastern time zone (GMT -5).

The San Mar Census Designated Place has a U1 Census Class Code which indicates a census designated place with an official federally recognized name. It also has a Functional Status Code of "S" which identifies a statistical entity.

A Census Designated Place (CDP) is a statistical counterpart to a self-governing (incorporated) place such as a city, town, or village. A CDP is not a legal entity and has no governmental functions.

San Mar, MD Data & Demographics (As of July 1, 2025)

POPULATION
Total Population	368 (100%)
Population in Households	251 (68.2%)
Population in Families	158 (42.9%)
Population in Group Quarters¹	117 (31.8%)
Population Density	790
Diversity Index²	37


INCOME
Median Household Income	$92,045
Average Household Income	$121,519
% of Income for Mortgage⁴	25%
Per Capita Income	$45,390
Wealth Index⁵	120
Socioeconomic Status Index⁶	Moderate (55.4)

HOUSING
Total HU (Housing Units)	143 (100%)
Owner Occupied HU	111 (77.6%)
Renter Occupied HU	23 (16.1%)
Vacant Housing Units	9 ( 6.3%)
Median Home Value	$371,277
Average Home Value	$415,586
Housing Affordability Index³	94

HOUSEHOLDS
Total Households	134
Average Household Size	1.87
Family Households	64
Average Family Size	2.00

NOTES

Group Quarters - a place where people live or stay in a group living arrangement. Includes college residents halls, nursing facilities, military barracks, and correctional facilities.
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 races 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.
The Housing Affordability Index base is 100 and represents a balance point where a resident with a median household income can normally qualify to purchase a median price home. Values above 100 indicate increased affordability, while values below 100 indicate decreased affordability.
The % of Income for Mortgage quantifies the percentage of median household income dedicated to mortgage payments on a home priced at the median value (assuming a 30-year mortgage and a 20% down payment).
The Wealth Index is based on a number of indicators of affluence including average household income and average net worth, but it also includes the value of material possessions and resources. It represents the wealth of the area relative to the national level. Values above or below 100 represent above-average wealth or below-average wealth compared to the national level.
The Socioeconomic Index ranges from zero (lowest relative status) to 100 (highest relative status). This measure quantifies disparities in social position of an area's inhabitants and is built from a broad range of demographic, housing, and socioeconomic inputs. More information on this measure can be found in Esri's SEI tutorial.

San Mar, MD - Peer Comparisons by Rank and Percentile

The table below compares San Mar to the other 536 incorporated cities, towns and CDPs 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.

GROWTH RATE / YEAR	2020-2025	2025-2030
Population	0.10%	0.11%
Households	0.00%	0.15%
Families		9.12%
Median Household Income		4.59%
Per Capita Income		1.89%
Owner Occupied HU		0.71%

Variable Description	Rank	Percentile
Total Population	# 408	24th
Population Density	# 336	38th
Median Household Income	# 296	45th
Housing Affordability Index	# 345	64th
Per Capita Income	# 282	48th
Diversity Index	# 356	34th

San Mar, MD Profile: Facts & Data

San Mar, Maryland - Basic Facts

San Mar, MD Data & Demographics (As of July 1, 2025)

POPULATION

INCOME

HOUSING

HOUSEHOLDS

GROWTH RATE / YEAR

San Mar, MD - Peer Comparisons by Rank and Percentile

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