Maryland's 4th congressional district wraps around the eastern edge of Washington, D.C., taking in most of Prince George's County and a small portion of Montgomery County. It is home to several racially diverse middle-class suburbs, including College Park, Fort Washington, Greenbelt, and Laurel. With a median household income of $80,808, it is the wealthiest black-majority district in the United States.^[1]

Like much of the Washington metropolitan area, the 4th district is substantially influenced by the footprint of the nearby federal government. More than 22% of working adults in this district are employed in the public sector. The Washington Metro provides easy access into the nation's capital, where many employees make daily commutes. Various government entities also sit within the 4th district, most notably the United States Census Bureau, NASA's Goddard Space Flight Center and the Beltsville Agricultural Research Center. The University of Maryland, College Park—the state's flagship public institution of higher education—is another major presence.

Throughout much of the 20th century, the area within this district was predominately white. But as a thriving black middle class emerged in the region and laws eliminating racial discrimination in housing were passed, many African Americans opted to leave Washington for Prince George's County in search of a better quality of life. By the early 1990s, the county had become majority black, and today white voters comprise just 11% of the 4th district. Recently, the district has experienced large amounts of immigration from El Salvador, Guatemala, and Honduras in Central America, leading to the district having the largest Latino population in Maryland and one of the largest Central American populations out of any district.^[3] These racial transformations have turned the district into one of the nation's most Democratic seats, with a Cook Partisan Voting Index rating of D+40.^[2] In 2022, Democrat Glenn Ivey was elected to represent it with 90.1% of the vote.

Maryland's fourth congressional district was one of the about 50 original congressional districts. When it was organized in 1788, it covered Baltimore, Baltimore County, and Harford County. According to the 1790 census, the fourth district had a population of 53,913, nearly 20% of whom were slaves.^[4]

In 1792, the fourth district was moved to western Maryland, with its eastern boundary being a north to south line running about the midpoint of Frederick County, Maryland. The new district had a population of 36,026, with less than 10% of the population being slaves.^[5] The 1800 census population was 38,015, and the boundaries remained unchanged in 1802.^[6]

Since 2023, the following communities have postal addresses within the 4th district.^[7][8]

• Maryland's congressional districts
• List of United States congressional districts