High Quality Content by WIKIPEDIA articles! The Walnut Street Theatre (or simply The Walnut), located in Philadelphia, Pennsylvania at 825 Walnut Street, is the oldest continuously operating theatre in the English-speaking world and the oldest in the United States. The venue has three stages: the Mainstage, for the company`s primary and larger productions, the Independence Studio on 3, a studio located on the building`s third floor for smaller productions, and the Studio 5 on the fifth floor, which is rented out for independent productions.