American Kennel Club
The main US registry, which keeps its own studbook, recognises a shorter list of breeds than the FCI and sorts them into seven groups.
The AKC registers dogs directly rather than federating national clubs, and it recognises breeds through its own process, with a waiting room — the Foundation Stock Service — for breeds working toward full recognition. Its seven groups are the ones most English-language breed writing uses by default.
Comparing registries is where confusion starts. A breed can be long established under the FCI and not recognised by the AKC, or split into two breeds by one body and treated as varieties of one by the other. Neither list is the definitive census of dog breeds, which is a good reason to be sceptical of any single number for how many exist.