 The Maple Valley Historical Society keeps records on the city's past, with two historical museums holding artifacts such as the city's first fire engine and photographs of old places in and around the city like Gaffney's Grove.The city of Maple Valley was officially incorporated on August 31, 1997.The Green to Cedar River trail runs through the city, along SR 169 and Witte Road while passing through the former Gaffney's Grove site, now the Lake Wilderness City Park.