 The Rocky Mountain Horse is a horse breed developed in the state of Kentucky in the United States . Despite its name , it originated not in the Rocky Mountains , but instead in the Appalachian Mountains . A foundation stallion , brought from the western United States to eastern Kentucky around 1890 , began the Rocky Mountain type in the late 19th century . In the mid @-@ 20th century , a stallion named Old Tobe , owned by a prominent breeder , was used to develop the modern type ; today most Rocky Mountain Horses trace back to this stallion . In 1986 , the Rocky Mountain Horse Association was formed and by 2005 has registered over 12 @,@ 000 horses . The breed is known for its preferred " chocolate " coat color and flaxen mane and tail , the result of the relatively rare silver dapple gene acting on a black coat , seen in much of the population . It also exhibits a four @-@ beat ambling gait known as the " single @-@ foot " . Originally developed as a multi @-@ purpose riding , driving and light draft horse , today it is used mainly for trail riding and working cattle . 
