Garrett County Courthouse is located at 203 South Fourth Street, Oakland MD 21550; phone: 301‑334‑8970.
Garrett, the youngest of the counties of Maryland, was carved out of territory belonging to Allegany County in 1872. Its first election for county offices was held in January, 1873. John W. Garrett, then president of the Baltimore and Ohio Railroad, for who the county was named, was instrumental in its establishment. It is the largest county in the state at approximately 660 square miles.