The Deering Street Historic District is a historic district in the Downtown and Parkside neighborhoods of Portland, Maine. Encompassing all of Deering Street and much of State Street, as well as adjacent portions of Congress and Mellen Streets, it is a cohesive collection of high quality architect-designed buildings from the second half of the 19th century, that were originally predominantly residential in nature. The district was added to the National Register of Historic Places in 1983.