Here's a bit of history:
* The breed was developed in the 19th century by Reverend John Russell, an English clergyman. He was a fox hunter and wanted a dog that was small, athletic, and tenacious to hunt foxes.
* The breed was originally known as the "Parson Russell Terrier".
* Today, Jack Russell Terriers are recognized by several kennel clubs worldwide, including the American Kennel Club.
So, while Jack Russell terriers are popular in America, they're actually a British breed with a long and fascinating history.