The carriage road system is unique among our national parks. Conceived by John D. Rockefeller, Jr., it was built under his direction (and with his money) between 1913 and 1940,
According to the system's principal historian, Anne Rockefeller Roberts (see Recommended Reading in the Bar Harbor pages), the system comprised 57 miles of roads. Current estimates vary, but the system today consistes of approximately 51 miles of interconnecting roads, of which about 45 miles occur within the boundaries of the park.
Rockefeller built the roads partly to provide himself and his friends a scenic transportation system free of the interference of the automobile (autos became legal in the Bar Harbor area in 1913 and island-wide in 1915). Because of this, the roads were designed to allow horses and their riders or carriages to easily ascend the hills, ridges, and lower slopes of the island's mountains. As a result, the roads are also well suited to walking, cycling, and cross-country skiing. Rockefeller strongly believed that the natural landscape shoud be protected, but at the same time it should be made available to people (this viewpoint, incidentally, occasionally put him in conflict with some of the other pioneers in the development of Acadia National Park). Thus, the twists and turns of the roads and the approaches to the bridges were designed---within the constraints of topography and being horse-friendly---to provide scenic vistas. In his dedication to this (according to Anne R. Roberts), he was not at all bashful about personally moving the stakes defining a proposed route in order to improve the view.
Today, the system is maintained much as Rockefeller would have wanted. No motorized vehicles are allowed. Horses are allowed on all roads except for the With Hole and Eagle Lake loops. Bicycles are not allowed on the roads of the private lands in the southern part of the system. In winter, some stretches of the system are groomed for cross-country skiing. The system also serves as access to many of the hiking trails of the park. Thanks to the efforts of Friends of Acadia ( http://www.friendsofacadia.org ) and many benefactors, the carriage roads---and the hiking trails---of the park are now endowed, thus guaranteeing their maintenance. This, if not unique, is also unusual in the national park system.