Middle Brook, Missouri, is a small, unincorporated community that sits on the Iron/ Saint Francois County line. The area was first settled in the late 1700s, when an abundance of iron ore was discovered in the local mountains. Middle Brook and its surrounding areas became a part of the United States after the Louisiana Purchase in 1803. The population of the town diminished as the area's natural resources were depleted. Today, Middle Brook is known for its rich Civil War history and beautiful natural landscapes.