The Glen of Imaal Terrier (Irish: Brocaire Uí Mháil) is a breed of dog of the terrier category and one of four Irish terrier breeds. It is sometimes called the Irish glen of imaal terrier or the Wicklow Terrier, and the name of the breed is often shortened by fanciers to just Glen.
The breed originates in, and is named for, the Glen of Imaal in County Wicklow, Ireland. It was recognised first by the Irish Kennel Club in 1934 and most recently by the American Kennel Club in 2004.
Reportedly, the glen of imaal terrier history began during the reign of Elizabeth I, who hired French and Hessian mercenaries to put down a rebellion in Ireland. After the conflict, many of these soldiers settled in the Wicklow area. They brought with them their low-slung hounds, which they bred with the local terrier stock, eventually developing a distinctive breed that became known as the Glen of Imaal Terrier.
Glens were originally used for eradicating vermin such as rat, fox, badger, and otter, and also as a general-purpose farm dog for herding and family companionship. Unlike many other terriers, they are “strong dogs” rather than “sounders”—they were bred to work mute to ground, going silently into dens after their quarry rather than barking at it to alert their handlers. In hunting trials, which used to be required by many kennel clubs for championships, Glens were disqualified if they sounded at the quarry.