Washington, D.C.: Not just a city in Maryland.
Since moving to San Diego, it's come to my attention that many Americans need a geography refresher. A brush up on US Government 101 wouldn't hurt either.
To the many people that have seen my DC license and/or license plate and commented that they had always thought Washington DC was a city in Maryland or Virginia, here is a quick refresher from Encyclopedia Britannica:
"Washington, in full Washington, D.C. (“District of Columbia”), city and capital of the United States of America. It is coextensive with the District of Columbia (the city is often referred to as simply D.C.) and is located on the northern shore of the Potomac River, at the river’s navigation head—that is, the transshipment point between waterway and land transport. The state of Maryland borders the District of Columbia to the north, east, and west, and the state of Virginia borders the District on the southern shore of the Potomac River."