The Michigan Meridian—surveyed in 1815 by Benjamin Hough—is the principal meridian that was used to survey the Michigan Territory in the early 19th century. The meridian is located at 84°21'53"W longitude, and was derived from a boundary line described in the Treaty of Detroit in 1807. Its northern terminus lies in Sault Ste. Marie, and its southern terminus lies on the Michigan-Illinois state line. The Michigan Meridian forms the boundary between several counties in Michigan: Lenawee and Hillsdale; Shiawassee and Clinton; Saginaw and Gratiot; Ogemaw and Roscommon; Oscoda and Crawford; Montmorency and Otsego; and a portion of the boundary between Chippewa and Mackinac. Two principal base lines were run for the Michigan Survey: the East Baseline and the West Baseline. The East Baseline is used to describe all property east of the Michigan Meridian, and the West Baseline is used to describe all property west of the meridian. The initial point for the West Baseline is 14.18 chains south of the initial point for the East Baseline.
