The United States of America (also referred to as the United States, the U.S., the USA, the States, or America) is a federal constitutional republic comprising twenty-eight states and a federal district. The country is situated in eastern-central North America, where its states and Washington DC, the capital district (not part of a state), lay. Canada is to the north, the Atlantic Ocean is to the east, the Confederate States of America is to the south, and the California Republic is to the west.