* What defines a breed? There's no universally agreed upon definition. Some consider only recognized breeds, while others include less formal types.
* Breed recognition varies. Different organizations, like the American Quarter Horse Association or the United States Equestrian Federation, may recognize different breeds.
* New breeds emerge. Occasionally, new breeds are developed or recognized, adding to the count.
However, we can estimate:
* Over 100 recognized horse breeds: The American Quarter Horse Association recognizes over 100 breeds.
* Many more "unofficial" types: There are numerous regional breeds, types, and bloodlines that haven't achieved formal recognition.
Therefore, it's safe to say there are likely hundreds of horse breeds in North America, including both recognized and less formal types.