The Delaware Otsego Corporation (DO) is an American railway holding company which owns the subsidiary New York, Susquehanna and Western Railway as well as other, smaller branch line railroads, collectively known as the DO System. It is headquartered in Cooperstown, New York in Otsego County. Once known for operating a successful family of short line railroads throughout New York and New Jersey, the only remaining active operation is the New York, Susquehanna & Western and its leased lines now known as the Central New York Railroad.