The city is also home to the Sycamore Historic District, an architecturally interesting area containing over 200 individual properties. The district was established in 1978 when it was added to the National Register of Historic Places. The area is bounded in an irregular pattern along Main and Somonauk Streets but contains portions of several other streets and includes much of the downtown commercial district and residential areas north and south of downtown. During the summer, the Sycamore Historical Society offers guided walking tours with a local historian.