Offering a good example of an evolved, small, mid-19th-century, water-powered gristmill, and one of the few known extant mills in Greene County, the A. J. Long Mill is a two-story frame building constructed around 1835 to replace an earlier mill. Rehabilitated with a one-and-a-half-story office addition in 1895, along with the introduction of new milling technology, Long Mill stands in the Blue Ridge Mountain community of Shifflet Hollow. One of the few surviving industrial buildings in the area, the structure has exterior and interior millworks that remain remarkably intact. Long Mill served farmers and area residents until around 1939, when the last known miller departed his post. Several restorations in the recent past were all completed employing historically appropriate materials and execution.