A bowling team in a 1922 Norwich, Connecticut newspaper called themselves the "Swamp Yankees". In 1935, the New York Times labeled Swamp Yankees as those driven out of a New England mill town by immigrants.
In a 1922 Norwich, Connecticut newspaper, a bowling team was known as the "Swamp Yankees".  The New York Times in 1935 described them as being people displaced from a New England mill town due to immigration.