While the American Kennel Club only recognizes a few types of spaniels, there are eighteen different types available throughout the world. The most common type of spaniel in the U.S. is the American Cocker Spaniel, which highly ranks in terms of popularity among American dog breeds.
The Cocker Spaniel breed began in Spain (which is where the "spaniel" comes from) around the 14th century. Owners originally used the dogs for falconry, and in the 19th century they found a new purpose: flushing out woodcock, hence the name Cocker Spaniel. Other popular types of spaniels include the Springer Spaniel, King Charles Spaniel, and Water Spaniel.