How many Jack Russell breeds are there?

The Jack Russell Terrier is primarily recognized as a single breed, but there are variations within it, such as the Parson Russell Terrier and the Russell Terrier. These variations differ slightly in size and conformation but share similar characteristics. The breed's classification can vary by different kennel clubs, leading to some confusion about the number of distinct types. Overall, while the Jack Russell is one breed, it encompasses a few recognized variations.