The Arboretum d'Olhain is a 2 hectare arboretum located in the Forêt Domaniale d'Olhain near Olhain, Fresnicourt-le-Dolmen, Pas-de-Calais, Nord-Pas-de-Calais, France. It is open daily without charge.
See also List of botanical gardens in France National Forest (France)
References Parc d'Olhain L'Echo des Chênaies entry Ecogardes Été 2008 (French)