Washington, D.C. is the capital of the United States, a federal district rather than a state, situated on the Potomac River between Maryland and Virginia. Planned from scratch in the 1790s as a purpose-built seat of national government, the city is organized around the National Mall and is home to the country’s three branches of federal power.

Where Is Washington, D.C. Located?

Washington, D.C. sits on the north bank of the Potomac River on land ceded by Maryland, bordered by the state of Maryland to the north and east and by Virginia across the river to the south and west. It is not part of any U.S. state; it is a federal district governed under the authority of the U.S. Congress, with a locally elected mayor and city council handling day-to-day municipal affairs. Its population exceeded 680,000 as of a mid-2010s estimate from the Mayor’s office, the highest level the city had recorded since the 1970s, after decades of population decline followed by renewed growth driven largely by migration into the city, according to an official release from the Mayor’s office.

A Brief History of Washington, D.C.

The site for the new federal capital was chosen as part of the Residence Act of 1790, a compromise that resolved a dispute over the location of the national government. French-born engineer Pierre Charles L’Enfant drew up a plan in 1791 calling for a wide, tree-lined promenade connecting the future Capitol to a monument honoring George Washington, an axis of ceremonial and democratic space that still defines the city’s center. For much of the 19th century the area envisioned by L’Enfant remained undeveloped and disorganized, scattered with gardens, a canal, and unrelated buildings, according to the National Park Service, which manages the Mall today. A comprehensive 1902 redesign known as the McMillan Plan cleared away the obstructions, filled in the old canal, and created the long open lawn framed by museums that visitors recognize now.

Government and the National Mall

Washington, D.C. houses all three branches of the federal government: the Congress at the Capitol, the presidency at the White House, and the Supreme Court in its own building nearby. The National Mall, running between the Capitol and the Potomac, functions simultaneously as a park, a ceremonial ground, ,an educational corridor lined with Smithsonian museums, and a traditional site for national celebrations and protest gatherings, a role the NPS describes as embodying continuity between the country’s founding ideals and its contemporary civic life.

What Is Washington, D.C. Known For?

Among the Mall’s monuments, the Washington Monument is the city’s single most recognizable structure: a 555-foot, 5-1/8-inch marble obelisk honoring the nation’s first president. Architect Robert Mills designed it in 1845, and it was built in two phases, a private effort from 1848 to 1854 that stalled for more than two decades after funding collapsed, followed by a federally funded completion between 1876 and 1884 overseen by the Army Corps of Engineers, according to the National Park Service. When finished in 1884, it was the tallest structure in the world. The National Park Service has managed the monument since 1933.

Why Washington, D.C. Matters

Washington, D.C. matters as the seat of government for the United States, the physical location where federal law is written, executed, and adjudicated, and as a deliberately symbolic landscape designed to express democratic ideals through its architecture and open public space. Its combination of political function and monumental design makes it both a working capital and a national civic monument in its own right.

Key Takeaways

• Washington, D.C. is a federal district, not a state, created by the Residence Act of 1790 on land along the Potomac River.
• Pierre Charles L’Enfant’s 1791 plan and the 1902 McMillan Plan together shaped the National Mall’s open, monumental layout.
• The city hosts all three branches of the U.S. federal government: Congress, the presidency, and the Supreme Court.
• The Washington Monument, completed in 1884 after a 22-year funding halt, was the tallest structure in the world at the time.
• D.C.’s population passed 680,000 in the mid-2010s, its highest level in roughly 40 years.

Sources

• Office of the Mayor, District of Columbia, “Washington, DC Population Now Highest in 40 Years”
• U.S. National Park Service, “The Mall”
• U.S. National Park Service, “History & Culture, Washington Monument”

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed October 5, 2026Researched and drafted with AI assistanceReport an issue