Michigan Meridian

The Michigan meridian is the principal meridian (or north-south line) used as a reference in the Michigan Survey, the survey of the U.S. state of Michigan in the early 19th century. It is located at 84 degrees, 21 minutes and 53 seconds west longitude at its northern terminus at Sault Ste. Marie, and varies very little from that line down the length of the state.

The meridian was surveyed by Benjamin Hough in April 1815. The meridian was selected because it formed one of the principal boundary lines defined in the Treaty of Detroit in 1807, which was the first large cession of land by Native American peoples to the United States in the Michigan Territory. In that treaty, the boundary line was described as running due north from the mouth of the Auglaize River on the Maumee River, which was the site of Fort Defiance (now Defiance, Ohio).

Michigan's baseline, which today forms the northern border of Wayne, Washtenaw and other counties, was surveyed at the same time by Alexander Holmes. Although regulations governing the U.S. Public Land Survey System would later specify that the baseline should be a true parallel of latitude, this was not the case in earlier surveys, including the Michigan survey. Some roadways were laid out for both survey lines, but there was no intersecting of roadways coinciding with the intersecting of survey lines. Several segments of the Michigan Meridian correspond with a road bearing the name Meridian Road.

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