The archaeology at Ashland has greatly added to our knowledge of the site. The remains of a circular, brick, plastered lined feature discovered behind the main house may relate to efforts to irrigate the gardens. A large cistern found just off the back veranda showed innovative use of limestone filtering, probably to enhance water quality.
The archaeology suggests that many outbuildings were needed to run the Ashland plantation. Kitchen related outbuildings found during archaeological investigations include a small square foundation near the kitchen that may have been a cheese and butter house, and a large circular foundation found just east of the two standing ice houses that may represent a third ice house or some other sort of cold storage building. Livestock was always an important part of the Ashland plantation, and remains of two barns and a smaller support outbuilding were found southwest of the house. Slaves provided much of the essential labor at Ashland, and archaeology has resulted in the location of remnants from slave quarters that were located just north of the present formal garden. Other below ground features found at Ashland many small features like post molds or small trash pits, or larger cisterns and privies.
What was not found during the survey was also important – no outbuildings or work areas were found in the area immediately behind the main house, in what Henry Clay called his pleasure grounds and where a circular walking path was located. On many plantations this area behind the main house was a heavy use area, but Ashland followed a more European example of having an area set aside for contemplation and leisure.