Unterallgäu is a Kreis (district) in the southwestern part of Bavaria, Germany. Neighboring districts are (from the north clockwise) Neu-Ulm, Günzburg, Augsburg, Ostallgäu, Oberallgäu, and the districts Ravensburg und Biberach in Baden-Württemberg. The district-free city Memmingen in the west of the district is nearly surrounded by the district.