The Arboretum de Sant Guillem (Saint Guillaume in French, 8 hectares) is an arboretum located in Le Tech, Prats-de-Mollo-la-Preste, Pyrénées-Orientales, Languedoc-Roussillon, France. The arboretum was created in 1958 and contains about fifty varieties of conifers and deciduous trees, once a nursery for the Office National des Forêts but still well-marked, with hiking trails throughout.