California: Meghan Markle
Markle wasn't always the "royalty" type. In fact, she lived an extremely down-to-earth life before she met Prince Harry. She grew up in Los Angeles, studied at Northwestern University, and she took tiny roles in TV shows and movies before she met her royal husband.
Off to the Races
It wasn't until Markle got a role on Suits that she started getting noticed a bit more. Fortunately for her, Prince Harry took notice of who she was. After that, she became a royal celebrity. Obviously there are a ton more famous people to come out of California, but on the world scale, Markle is the most famous by a long shot.