It's been more than a century since Connecticut had big league baseball, but in the 1870s, Middletown, Hartford, and New Haven fielded professional teams that competed at the highest level. By the end of the decade, when the state's final big league team, Mark Twain's beloved Hartford Dark Blues, left the National League, baseball's transition from amateur pastime to major league sport had been accomplished. And Connecticut had played a significant role in its development. The history of the Nutmeg State's three major league teams is described here in full, and the author thoughtfully examines their influence within the regional baseball scene.