They are not banned in any entire states of the US. They are banned at the municipal/city levels, and some counties (like Miami-Dade county in Florida). Ohio is considering a state-wide ban.
There are several cities that have also banned other breeds.
LEOLA, SOUTH DAKOTA has made it illegal to own Rottweilers, Pit Bulls, Dobermans, German Shepherds and Bull Mastiffs
Some of the UK has bans or restrictions in place for more than 40 different breeds, Italy more than 100 breeds. So the bans don't only affect pit bulls.
New York Housing Authority has banned: EVERY dog that weighs more than 25 pounds, plus Akita Inu, Alangu Mastiff, Alano Español, American Pit Bull Terrier, American Staffordshire Terrier, Argentine Dogo, Bedington Terrier, Boston Terrier, Bull and Terrier, Bull Terrier
Bully Kutta, Cane Corso, Dogue de Bordeaux, Dogo Sardesco, English Mastiff, Fila Brasileiro, Gull Dong, Gull Terr, Irish Staffordshire Bull, Korea Jindo Dog, Lottatore Brindisino, Neapolitan Mastiff, Perro de Presa Canario (Canary dog), Perro de Presa Mallorquin (Ca de Bou), Shar Pei, Staffordshire Bull Terrier, Tosa Inu