It is surrounded by ( from the south and clockwise ) the districts of Ravensburg , Sigmaringen , Reutlingen and Alb-Donau , and the Bavarian districts Neu-Ulm , UnterallgÃ u and the district-free city Memmingen . It is bounded by ( from the south and clockwise ) the districts of Ravensburg , Sigmaringen , Reutlingen and Alb-Donau , and the Bavarian districts Neu-Ulm , UnterallgÃ u and the district-free city Memmingen .