Antelope Island, with an area of 42 square miles (109 km2), is the largest island of 10 islands located within the Great Salt Lake, Utah, United States. The island lies in the southeastern portion of the lake, near Salt Lake City and Davis County, and becomes a peninsula when the lake is at extremely low levels.

The first known non-natives to visit the island, "we rode on horseback over salt from the thickness of a wafer to twelve inches", were John C. Fremont and Kit Carson during exploration of the Great Salt Lake in 1845, who "were informed by the Indians that there was an abundance of fresh water on it and plenty of antelope".[2] It is said they shot a pronghorn antelope on the island and in gratitude for the meat they named it Antelope Island.

Antelope Island has natural scenic beauty and holds populations of pronghorn, bighorn sheep, American bison, porcupine, badger, coyote, bobcat, and millions of waterfowl. The bison were introduced to the island in 1893, and Antelope Island Bison Herd has proven to be a valuable genetic pool for bison breeding and conservation purposes. The bison do well because much of the island is covered by dry, native grassland.

The geology of Antelope Island consists mostly of alluvial plains with prairie grassland on the north, east and south of the island, along with a mountainous central area of older Precambrian metamorphic and igneous rocks and late Precambrian to Paleozoic sedimentary rocks, covered by a thin layer of Quaternary lake deposits, colluvium and alluvium. The Precambrian deposits on Antelope Island are some of the oldest rocks in the United States, older even than the Precambrian rocks at the bottom of the Grand Canyon.

Antelope Island State Park is a Utah State Park and the entire island is included in the park. Early in the 20th Century, because of its wildlife and scenic beauty, some suggested that Antelope Island should become a National Park, but the movement never came to fruition.

The Fielding Garr Ranch is a ranch located on the southeastern portion of Antelope Island State Park in the Great Salt Lake, Utah, USA and is part of the Utah State Parks system.

The Fielding Garr Ranch is located at Garr Springs which is one of the strongest and most consistent springs of the 40 known springs on Antelope Island, though even this spring has shown some signs of drying up in recent years. The ranch is one of the oldest working ranching operations in the Western United States. The ranch was initially established in 1848, the year after the first Mormon pioneers came into the Salt Lake Valley. Fielding Garr, a widower with nine children, was sent by the The Church of Jesus Christ of Latter-day Saints (LDS Church) to live on Antelope Island and establish a ranch to manage the church's Tithing Herds of cattle and sheep. The first building was an adobe house, built in 1848, and it is still in existence as the oldest building in Utah, built by pioneers of European descent, that still remains on its original foundation. The adobe ranch house was continuously inhabited thereafter until 1981 when the State of Utah prepared to set up Antelope Island as a Utah State Park. At various times other people tried to live on the island, but the harsh conditions, isolation and a lack of fresh water made it very difficult.

The ranch remained under the control of the LDS Church until 1870, when it was purchased by John Dooly, Sr. Dooly lived on the island and set up the Island Improvement Company to provide cattle and sheep ranching. At one point the island supported a population of 10,000 sheep and it was one of the largest sheep ranches in the United States. In 1893, John Dooly and William Glassman imported 12 American Bison to the island. Buffalo (American Bison) were becoming extinct over much of their range at the time, and he felt that their novelty value was high enough that he could ranch them, and charge people to hunt them.

Ranching continued until 1981, when Antelope Island State Park was established. The cattle and sheep were removed and the island park was created to protect the wildlife and allow park visitors to enjoy the scenic beauty and to camp, boat and visit the beaches of the Great Salt Lake.

Antelope Island has had multiple functions throughout the decades. Much of that is described above but includes the harbor of bison, sheepshearing and ranching, public tourism, etc.

The public is free to come to Antelope Island throughout the year (all seasons).

Visitors can reach Antelope Island by driving over the causeway that starts in Davis County (Syracuse)