District of Columbia
In 1790, the U.S. Congress set aside some land along the Potomac River to be used for a new capital. The land came out of both Virginia and Maryland. In 1846, the Virginia part was returned to Virginia. But the part from Maryland was still big enough for the capital.
In the 1970s and early 1980s, people tried to get Washington, D.C., to be treated more like a state, with a senator and a representative. But so far this hasn't happened — D.C. has one representative in Congress, but that person can't vote on any laws.
The U.S. capital is filled with important government buildings and monuments. It has the Capitol, the Lincoln and Jefferson memorials, the Washington Monument, and the White House. You can see the real Declaration of Independence at the National Archives, you can watch them making money at the U.S. Mint, and you can see space capsules at the Smithsonian Air and Space Museum. And that's just a start!
Washington, D.C., is not a state, is the twenty-third largest city in the United States, and has about 523,000 people. It's not a big area on the map — D.C. is only about 68 square miles.