The Pepco Harrison Window Gallery is located at 5210 Wisconsin Ave NW, DC, 20015. In 1940 the Potomac Electric Power Company (Pepco) built a substation near the Maryland border. The building was elegantly designed with six large display windows complimenting neighborhood architecture. For decades customers could pay their bills in person at this location. As the world moderized, the need for in-person payments waned and the space was converted to gallery space.