The Evolution of Michigan's
Legal Boundary
Few published maps
show Michigan’s true boundary. Michigan's
legal boundary does not stop at the shoreline of
the four Great Lakes that encircle it, but extends into them to include
almost 40,000 square miles of water, comprising 40% of Michigan's
area. Most maps of Michigan show only the upper and lower
peninsulas plus a few major islands. The U.S. Geological Survey
recognizes 420 named islands in the Great Lakes belonging to
Michigan.
Since statehood, eight challenges to the boundary have resulted in
adjustments that relinquished territory to Minnesota, Wisconsin, and
Ohio, but gained territory from Canada.
1. Sugar Island / St. George's Island in the
St. Mary's River: The Webster-Ashburton Treaty, signed August 9,
1842, settled a border
dispute with Great Britain in which Michigan gained governance
over Sugar Island (called St. George’s Island by the Canadians).
2. The Minnesota Sliver: The
Webster-Ashburton Treaty also settled the location of a point in Lake
Superior that subsequently caused Michigan to relinquish a sliver
of water to Minnesota.
3. The
Toledo Strip:
Part 1:
The boundary with Ohio was hotly contested in the 1830s as a result of
two surveys that left an areas of dispute amounting to 468 square miles
on the Michigan-Ohio boundary. At the time
of statehood, Michigan accepted the western portion of the Upper Peninsula instead of the
“Toledo Strip”.
Part 2:
By 1914 survey markers had disappeared and the referenced “North Cape”
of the Maumee river had eroded. To settle
the new dispute peacefully, the line was re-surveyed and marked with
sturdy granite pillars. Both sides agreed
to accept whatever lines were agreed by landowners on both sides of the
state line, resulting in a “sawtooth” shaped boundary .
4.
The Wisconsin Wedge: A Supreme Court decision March 1, 1926
awarded a sliver of land to Wisconsin. The
dispute arose because the original 1836 boundary description
referenced a situation that didn’t exist: The referenced Montreal River
did not originate from the Lake of the Desert.
5. The Green Bay Channel and Islands:
The 1836
boundary description described the line through northwest Lake Michigan
as “the most usual ship channel”. This
description needed clarification as two routes were in use. A 1926 Supreme Court decision chose the
northernmost ship channel, in which Michigan lost the intervening water
area and four islands: Plum,
Detroit, Washington, and Rock.
6. The Lake Erie Triangle: Another dispute with Ohio
brought into contention about 150 square miles of Lake Erie. Should the “northeast” line be a continuation
of the gentle angle created by the Toledo Strip, or should upon
reaching Lake Erie the line turn to a 45˚ angle? In
1970 the Supreme Court decided in favor of Ohio.
7. Menominee River Islands:
The
islands of the Menominee River were divided in half by the US Supreme
Court in 1926: Those north of “Quinnesec Falls” (now the site of Big
Quinnesec Dam) were awarded to Michigan, and those south of the falls were awarded to Wisconsin.
When is an Island
not an Island?
the U.S.
Supreme Court declared in the case Michigan v. Wisconsin, decided
November 22, 1926, that Merryman Island in Menominee County is “part of
the mainland of Michigan.”
Last updated
August 25, 2005
Page editor Kathleen Weessies.