Virginia ( , ), officially the Commonwealth of Virginia, is a U.S. state located in the South Atlantic region of the United States. Virginia is nicknamed the "Old Dominion" due to its status as the first colonial possession established in mainland British America, and "Mother of Presidents" because eight U.S. presidents were born there, more than any other state. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most populous city, and Fairfax County is the most populous political subdivision. The Commonwealth's estimated population is over 8.3 million.