Browns Park, originally named Brown's Hole, is an isolated valley, thirty-five miles long and five to six miles wide. It is bounded on the south by Diamond Mountain, a part of the Uinta Mountains, and on the north by Cold Spring Mountain. The valley is located in extreme northeastern Utah, northwestern Colorado, and south-central Wyoming. The Green River flows through the park and provided access to the area for the first Americans who traveled through the park.

Accounts of how Brown's Hole was named vary. Some claim it was named for Baptiste Brown, a French-Canadian fur trapper who arrived in 1827, while others claim that Baptiste Brown was an alias for Jean-Baptiste Chalifoux. A few argue that Brown is a fictional character invented long after Browns Park was named, and that the name comes from the brown physical appearance of the valley.

The first recorded visit to Browns Park was in 1825 by William Ashley and a group of fur trappers who floated down the Green River through Brown's Hole in bull boats made from hides. After that, many fur trappers and mountain men visited Brown's Hole; the list included Kit Carson, Joe Meeks, Jack Robinson, the Ceran St. Vrain party from Taos, New Mexico, who spent the winter of 1827-28 in Brown's Hole, and the Alexander Sinclair party who wintered there in 1831-32. Later, in 1837, William Craig, Philip Thompson, and a man named Sinclair established a trading post, known as Fort Davey Crockett, in Brown's Hole.

Explorer John Wesley Powell passed through the area during his first expedition in 1869 and began to refer it as "Brown's Park," a more appropriate and attractive name for the basin. The more mild winters of the location made it popular with the Indians and the subsequent fur trappers and cattlemen. Its isolation made it a haven for outlaws.

The historical record is not clear as to who was the first to bring cattle into Browns Park and who was the first to escape the law by hiding out in its remote location. Quite possibly they were one and the same since the line between cattleman and cattle rustler was often vague. Juan Jose Herrera, a native of New Mexico, and a small group of men arrived in Browns Park in 1870 intending to start a cattle business with cattle taken from herds passing through the area. The following year, George Baggs wintered a herd of 900 Texas cattle in Browns Park. He was so impressed with the spot that he encouraged others to relocate there.

By the late 1870s and early 1880s, a number of settlers had taken up land in the area. One of these, John Jarvie, opened a general store/trading post on the north bank of the Green River. The store, with its ferry across the river, served as a way station for travelers. In addition to the store, Jarvie pursued mining ventures and raised cattle and horses. He was murdered while he was alone at his store on 6 July 1909. Today, the Jarvie ranch and store is maintained as a historic site by the Bureau of Land Management and is open to visitors.

Cattlemen, cowboys, rustlers, settlers, and outlaws all intermingled in Browns Park, which was, at least through the 1930s, a place, in the words of writer John Rolfe Burroughs, "where the Old West stayed young." Outlaws like Butch Cassidy, the Sundance Kid (Harry Longabaugh), Matt Warner, Elza Lay, Tom Horn Ann Bassett "Queen of the Cattle Rustlers," and many others left their mark on the history of Brown's Park. Today, Browns Park is still used for some cattle grazing, but more important are the recreational activities pursued there, such as hunting, fishing, and river rafting.