Bethesda (//) is an unincorporated, census-designated place in southern Montgomery County, Maryland, United States, located just northwest of Washington, D.C. It takes its name from a local church, the Bethesda Meeting House (1820, rebuilt 1849), which in turn took its name from Jerusalem's Pool of Bethesda. The National Institutes of Health's main campus and the Walter Reed National Military Medical Center are in Bethesda, in addition to a number of corporate and government headquarters.
|• Total||34.2 km2 (13.2 sq mi)|
|• Land||34.0 km2 (13.1 sq mi)|
|• Water||0.2 km2 (0.1 sq mi)|
|Elevation||97 m (318 ft)|
|• Density||2,000/km2 (5,200/sq mi)|
|Time zone||UTC−5 (Eastern (EST))|
|• Summer (DST)||UTC−4 (EDT)|
|Area codes||301, 240|
|GNIS feature ID||0583184|
As an unincorporated community, Bethesda has no official boundaries. The United States Census Bureau defines a census-designated place named Bethesda whose center is located at , while the United States Geological Survey has defined Bethesda as an area whose center is at , slightly different from the Census Bureau's definition. The Bethesda Urban Planning District uses other definitions, the United States Postal Service (which defines Bethesda to comprise the ZIP Codes 20810, 20811, 20813, 20814, 20815, 20816, and 20817), and other organizations. According to the 2020 United States census, the community had a total population of 68,056.