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Marking the Boundary of Michigan's Upper Peninsula.
This finely executed federal survey map records the first successful attempt to define the boundary between Michigan and the Wisconsin Territory through astronomical observation and topographic reconnaissance. Compiled by Captain Thomas Jefferson Cram of the Corps of Topographical Engineers and drawn by Lieutenant Joseph Dana Webster, the map was prepared to accompany Cram’s formal report to the U.S. Senate, printed in Executive Document No. 170 and ordered to be reissued with maps on March 31, 1842.
The survey followed Michigan’s admission to the Union in 1837 and was commissioned to settle longstanding confusion about the state’s western boundary, which Congress had defined in 1836 as following the Menominee River to its source, thence by a portage to the Montreal River and down to Lake Superior. Earlier efforts to chart this line had failed to locate the requisite headwaters with sufficient precision. Cram’s expedition of 1840–41 undertook a comprehensive survey of the hydrology of the upper peninsula, connecting fixed astronomical points along the Menominee, Lac Vieux Désert, and the Montreal’s East Branch to establish a defensible geographic trace.
The resulting map extends from the confluence of the Rock and Mississippi Rivers in the south to the upper reaches of Lake Superior in the north, capturing the full course of the boundary under consideration. It incorporates data from earlier surveys by Captains Talcott and Abert, whose anchor points are labeled, and sets them into a uniform projection carefully described in the accompanying report. Place names are sparse: the map reflects a region only lightly settled by Euro-Americans at the time, with towns such as Milwaukee, Madison, and Chicago still in early stages of development. The presence of military posts (including Forts Winnebago, Howard, Crawford, and Snelling) underscores the strategic importance of the region at a moment when federal control remained tenuous.
The line established by Cram and formally recognized in the 1842 report formed the basis for the present-day boundary between Michigan and Wisconsin and was upheld in its essentials by the U.S. Supreme Court in Wisconsin v. Michigan (1926).
An early and important map from the federal cartographic program of the 1840s.
