The museum is housed in medieval buildings, including the Lacataye "keep" (14C), built out of a particular stone, so-called "coquillière" as it became incrusted with shells around 2 000 years ago. It is devoted to modern figurative sculpture between 1880 and 1950, presenting works by Charles Despiau and Robert Wlérick (who created the equestrian statue of Marshal Foch in Paris), both of whom hailed from Mont-de-Marsan. The garden contains monumental sculptures by Despiau.