is a former county
in the U.S. state
. It was established May 23 1857
, as a county in the Minnesota Territory
. It comprised the 24 northern townships
, now forming the northern half of Pine County, Minnesota
. The Buchanan County seat was Sandstone
. This county was dissolved and incorporated with Pine County in 1861.
In recent years, residents of Pine County proposed dividing the county in half, re-introducing Buchanan County. The referendum for this proposal went to ballot in 2000 and was rejected.