WATCH: Where the Buffalo Roam

The bison roam a pasture near the south shore of O.C. Fisher reservoir between Mercedes St., the dam, the park entrance and the spillway.  

The longhorns are in an adjacent pasture and another location near the center of the park. 

Check out the photos below: 

According to Wikipedia, the American bison or American buffalo used to roam the continent freely in large herds. It nearly became extinct by a combination of commercial hunting and slaughter in the 19th century and introduction of bovine diseases from domestic cattle. With a population in excess of 60 million in the late 18th century, the species was down to just 541 animals by 1889. Recovery efforts expanded in the mid-20th century, with a resurgence to roughly 31,000^[5] wild bison today, largely restricted to a few national parks and reserves. 

According to TPWD, The Official State of Texas Longhorn herd was preserved. Western writer J. Frank Dobie recognized the Texas Longhorn decline in the early 1920s. He felt it was important to preserve the breed that held such a significant place in Texas history. With help from businessman Sid Richardson and rancher Graves Peeler, Dobie procured a herd of typical longhorns. They donated the animals to the Texas Parks Board in 1941 as the state herd. The board placed the herd at Lake Corpus Christi State Park near Mathis. The search continued for more of the scarce longhorns. In 1942, the board placed a second herd at Lake Brownwood State Park.

The Historical Commission and Texas State Parks now jointly manage the Official State of Texas Longhorn Herd. Members of the herd live at San Angelo, Copper Breaks, Palo Duro Canyon and Lyndon B. Johnson state parks.