West Coast Swing came out of California in the 1930s. The person that got the most credit for it was a dancer/choreographer named Dean Collins. He came from New Jersey to California to work in the movie industry and was asked to choreograph a swing dance scene. The director wanted more people on the dance floor. To accomplish that, Dean had the dancers move forward and back in a slot. Therefore came the birth of a new dance.
As more people on the west coast started doing this version of swing, the dance studios began teaching it. It was originally called "Western Swing" or "Sophisticated Swing" to differentiate it from the more familiar East Coast Swing. In 1959 dance organizations and studios changed the name officially to West Coast Swing.