According to the United States Census Bureau, Six Mile Run had a total area of 7.484 square miles, including 7.476 square miles of land and 0.008 square miles of water.
Van Liew-Suydam House, 280 South Middlebush Road. It was built in the 18th century by Peter Van Liew. Joseph Suydam later built the part of the house that is visible today. The newest and largest portion of the house was built in 1875. Although the most recent long term owner of the house was named French, the house has been named after its two initial owners.
Hageman Farm, 209 South Middlebush Road
Wyckoff-Garretson House, 215 South Middlebush Road
In 1710, a congregation of the Dutch Reformed Church formed the Six Mile Run Reformed Church. The first building was replaced by a new building in 1766 and was later replaced in 1817 by a third structure on the same site. The current building replaced the 1817 church that was destroyed by fire in 1879. The Frelinghuysen Memorial Chapel was added in 1907 and the Fellowship Hall was dedicated in 1958.
The proposed Six Mile Run Reservoir Site is adjacent to the Delaware and Raritan Canal and included a large portion of the Six Mile Run Watershed in central Franklin Township. In 1970, the land for the reservoir was acquired by the State through the New Jersey Department of Environmental Protection, Division of Water Resources as a future reservoir and recreation area and included many of the properties later listed as contributing to the Six Mile National Register Historic District. The reservoir was never built, and in 1993 administration of the area was transferred to the Division of Parks and Forestry.
Today the Six Mile Run Reservoir site is maintained as a State Park and includes several trails that are used primarily by mountain bikers, hikers, and horseback riders. It has of twisting single track maintained by JORBA. Access to the park can be found at the large parking lot on Canal Road near Six Mile Run Road, from the parking lot of the private soccer club on Route 27, and from several smaller parking areas on roads that traverse the park. Because part of the land at the site was taken out of cultivation 39 years ago, the process of "old field succession" has now yielded up trees and foliage that are unique among state park lands. In the section between Canal Road and South Middlebush Road, there are postings describing the foliage and the natural process. The "Red Dot" hiking trail, which runs between Canal Road and South Middlebush Road, has now been extended from South Middlebush Road up to NJ Route 27. There is a new White Trail, not fully blazed but very usable, running from a left fork off Red Dot near South Middlebush Road, to a parking lot off Jacques Lane.
