From wikipedia:

The Collegiate Shag (or “Shag”) is a partner dance done primarily to upper tempo jazz music (usually 200+ beats per minute). It belongs to the swing family of American vernacular dances that arose in the 1920s, 30s, and 40s. It most likely originated in North Carolina, but quickly spread across the United States during the 1930s and as far as Australia by the 1940s.