The asylum had its own museum based in the main building. In 1976, Bedford Museum was asked to come in and clear the asylum museum as the hospital needed the space. Many artefacts, paperwork and documents were removed and taken back to Bedford where they were sorted, photographed and catalogued. The artefacts remain in storage in Bedford, and the paperwork and documents now reside in the Bedford Archive.
In March 2022, Fairfield Parish Council purchased some Three Counties Asylum artefacts from the private collection of Rich and Ross Knight and established a small museum within Fairfield Community Hall, Fairfield Park, in the grounds of the original Three Counties Asylum.