Detroit Island

Detroit Island is a mostly privately owned island in Lake Michigan in the southern part of the town of Washington in Door County, Wisconsin, United States. The island has a land area of 2.578 km² (0.9955 sq mi, or 637.12 acres).[1][2] The northern end of the island borders the waters of Detroit Harbor.

Detroit Island
Detroit Island.jpg
Facing the northern side of the island from the harbor
Detroit Island is located in Wisconsin
Detroit Island
Detroit Island
Detroit Island is located in the United States
Detroit Island
Detroit Island
LocationDoor County, Wisconsin
Coordinates45°19′17″N 86°54′58″W / 45.321487°N 86.916073°W / 45.321487; -86.916073Coordinates: 45°19′17″N 86°54′58″W / 45.321487°N 86.916073°W / 45.321487; -86.916073
Area637.12 acres (257.83 ha)
Highest elevation594 ft (181.1 m)
CountyDoor County
TownWashington Island

Grand Traverse Island State Park was founded in 1970 and protects sightly more than 5 acres (2.0 ha) of land on Detroit Island.[3] It consists of five discontiguous parcels[4] and there is no ferry access.


Fishermen working with nets on Detroit Island; from a postcard postmarked in 1909

The border between Wisconsin and Michigan was originally defined as "the most usual ship channel" into Green Bay from Lake Michigan but commercial routes existed both to the north and south of the island which lead to a border dispute. In 1936, the U.S. Supreme Court decision Wisconsin v. Michigan found that Detroit and three other islands were part of Wisconsin.

Nearby islandsEdit

Detroit Island is the long and narrow island at center-right. Beneath Detroit Island on the right is the much smaller Pilot Island, with Plum Island is at the lower left. Washington Island is in the distance.


  1. ^ "Detroit Island (Wisconsin)". Geographic Names Information System. United States Geological Survey.
  2. ^ "Detroit Island: Blocks 2109 thru 2112, Block Group 2, Census Tract 9801, Door County, Wisconsin United States Census Bureau". Retrieved 2020-03-29.
  3. ^ "Payment of State Aid to Municipalities for the payment year of 2005" (PDF). Wisconsin Department of Natural Resources. Retrieved 2016-02-26.
  4. ^ Hunting & Trapping Map Grand Traverse Island State Park, Wisconsin DNR PUB PR-2090, Rev. 9/11/2014