Potomac (listenⓘ) is an unincorporated community and census-designated place in Montgomery County, Maryland, United States. As of the 2020 census, it had a population of 47,018. It is named after the nearby Potomac River. A part of the Washington metropolitan area, many Potomac residents work in nearby Washington, D.C., and Northern Virginia.

The land that is now Potomac was first settled by Edward Offutt in 1714 after he was granted a 600-acre (2.4 km2) land grant of a region known as Clewerwell by Lord Baltimore. His grant of land was by the Tehogee Indian Trail, an Indian trade route built by the Canaze Native American nation in 1716[citation needed]. Throughout the 18th century, what became known as "Offutts Crossroads" was a small, rural community which served planters and travelers. In the 19th century, a few small dwellings had been built along with a tavern established in 1820. By the time of the Civil War, the community contained two general stores, a blacksmith shop, and a post office which served a community of 100.

Offutts Crossroads was renamed "Potomac" in 1881 by John McDonald. An Irishman and veteran of the Civil War, McDonald settled in Potomac around that time. He petitioned for the name change since postal officials were asking for brief names and there were already several other communities in the area with the name "crossroads".

By the turn of the 20th century, Potomac was growing. Thomas Perry, an operator of a nearby general store, built a house on the corner of Falls and River Roads in 1902. More residential structures were built on the northern section of Falls Road throughout the 1920s and 1930s. During the 1950s, Potomac was one of many communities in Montgomery County to experience suburbanization because of its proximity to Washington, D.C. Potomac quickly transformed from a rural farming community to a suburban community from the mid- to late 20th century.

Numerous original buildings within Potomac Village have been demolished for the construction of strip malls and modern office buildings. However, in the surrounding area, many of the old farmhouses remain, though some are confined within suburban developments. The Perry Store has been restored and still stands as part of a bank, although the building was moved 21 feet in 1986 to allow for a project to widen the intersection of Falls and River Roads.

Potomac's geographical focal point is Potomac Village, a small cluster of shops and businesses at the intersection of Maryland State Highway 189 (Falls Road) and Maryland State Highway 190 (River Road) northwest of Washington, D.C.

According to the U.S. Census Bureau, Potomac has a total area of 26.6 square miles (69 km2), of which 25.2 square miles (65 km2) are land and 1.4 square miles (3.6 km2), or 5.33%, are water. It includes the ZIP Code 20854 for properties and 20859 for US Post Office Boxes.

The climate is characterized by hot, humid summers and generally cool to cold winters with light snow. According to the Köppen climate classification system, Potomac has a humid subtropical climate, abbreviated "Cfa" on climate maps.

As of the 2010 census, there were 44,965 people living in Potomac, including 16,093 households. The population density was 1,790 inhabitants per square mile (690/km2). There were 16,642 housing units at an average density of 633.9 per square mile (244.8/km2). A 2017 ACS 5-Year Population Estimate cited 45,780 people living in Potomac.

As of 2010, the racial makeup of the CDP was 75.8% White, 4.6% African American, 0.1% Native American, 15.9% Asian, 0.01% Pacific Islander, 0.90% from other races, and 2.6% from two or more races. Hispanic or Latino residents of any race were 6.4% of the population.

Of the 16,093 households, 38.4% included children under the age of 18, 74.8% were married couples living together, 6.6% had a female householder and 16.8% were non-families. Fourteen percent of all households were made up of individuals, and 5.9% were persons living alone who were 65 or older. The average household size was 2.84 and the average family size was 3.10.

In 2019, the median property value in Potomac, MD was $893,000, and the homeownership rate was 87.6%.

In Potomac, the age distribution was 25.3% under the age of 18 (2010), 4.6% from 18 to 24, 21.3% from 25 to 44, 34.0% from 45 to 64 and 13.8% who were 65 or older. The median age was 44. For every 100 females, there were 91.6 males. For every 100 females 18 or older, there were 87.3 males.

The median income for a household in the CDP was $187,568 in 2017 dollars. Men had a median income of more than $100,000; women, $78,442. About 2.5% of families and 3.3% of the population were below the poverty line, including 3.6% of those under the age of 18 and 3.6% of those 65 and older.

Potomac has a branch of the Montgomery County Public Libraries.