The Territorial Legislature created Jackson County on January 12, 1852, from the south-western portion of Lane County and the unorganized area south of Douglas and Umpqua Counties. The county was named after President Andrew Jackson. John D. West was appointed to serve as the first Sheriff of Jackson County about five months after the county was formed.
Jackson County's borders originally ran south to California, west to the Pacific Ocean, and east to Lane County, and north to Umpqua and Douglas Counties. Over the years, the boundaries of the county were changed reflecting the creation of Coos, Curry, Josephine, Klamath, Lake, and Wasco Counties.
Jacksonville was designated as the first county seat in 1853. However, the city declined due to diminishing returns in the local goldfields and the construction in the 1880s of the Oregon and California Railroad, which bypassed the city. Medford, located five miles east of Jacksonville, benefited from the location of the railroad and the accompanying commerce and development. Jacksonville fended off suggestions to move the county seat until 1926 when Medford was selected as the county seat.
The historic Jacksonville Museum was the original location of the Sheriff’s Office & Jail. It remained there until 1926. Presently, the Main Sheriff’s Office is located at 5179 Crater Lake Highway in Central Point, and the Jackson County Jail is located at 787 W 8th St, Medford. The JC Jail was built in 1981.