Question: Henry Schoolcraft discovered a lake in what county?

Context paragraphs:
Schoolcraft County, Michigan: Schoolcraft County is a county located in the Upper Peninsula of the U.S. state of Michigan.  As of the 2010 census, the population was 8,485.  The county seat is Manistique, which lies along the northern shore of Lake Michigan.  The county is named in honor of Henry Schoolcraft, who explored the area with the expedition of Lewis Cass.  The county was founded in 1843 and organized in 1876.  The county is largely rural and forested, with much of the western portion of the county located within Hiawatha National Forest.

Schoolcraft Township, Kalamazoo County, Michigan: Schoolcraft Township is a civil township of Kalamazoo County in the U.S. state of Michigan.  The population was 7,260 at the 2000 census.  The township is named for Henry Schoolcraft, noted for conducting many early land surveys throughout Michigan.

Longfellow, Minneapolis: Longfellow is a defined community in Minneapolis, Minnesota which includes five smaller neighborhoods inside of it: Cooper, Hiawatha, Howe, Seward, and Longfellow.  Grouped with South Minneapolis between the city's eastern border with the Mississippi River and the Metro Blue Line , Longfellow takes its name from Longfellow neighborhood which in turn is named after Henry Wadsworth Longfellow.  The renowned American poet incorporated elements into his poem "The Song of Hiawatha" from Henry Schoolcraft's accounts of native Dakota lore in Minnesota which included Minnehaha Falls in Longfellow's southern tip.  The early reference of Highway 55 as Hiawatha Avenue, along the west border, may have influenced the naming decision when community borders were drawn in the 1960s.  Hiawatha Avenue is the main thoroughfare leading north into Downtown Minneapolis and south to the Minneapolis-Saint Paul Airport.

Mary Howard Schoolcraft: Mary Howard Schoolcraft (1820 – March 12, 1878) was an American writer, the author of the controversial pro-slavery novel, "".  She was the second wife of geographer, geologist and ethnologist Henry Schoolcraft.

John Schoolcraft House: John Schoolcraft House is a historic home located at Guilderland in Albany County, New York.  It was built about 1835 and is a distinctive Gothic Revival style dwelling.  It features gingerbread vergeboards, pinnacles with crockets, lancet windows, and horizontal beaded siding.  It was built by John L. Schoolcraft (1804-1860), U.S. Congressman and uncle of Henry Rowe Schoolcraft.

Schoolcraft State Park: Schoolcraft State Park is a state park of Minnesota, USA, on the banks of the Mississippi River near Grand Rapids and Deer River.  It was named for the explorer Henry Schoolcraft.

Lake Itasca: Lake Itasca is a small glacial lake approximately 1.8 sqmi in area.  It is notable for being the headwaters of the Mississippi River, and is located in southeastern Clearwater County, in the Headwaters area of north central Minnesota.  The lake is within Itasca State Park and has an average depth of 20 to 35 feet (6–11 m), and is 1,475 ft (450 m) above sea level.

Schoolcraft River: The Schoolcraft River is a tributary of the Mississippi River, approximately 30 mi (48 km) long, in northern Minnesota in the United States.  Although short, it is considered as the first major tributary of the Mississippi, since it is the first river that joins the Mississippi below its source that is nearly the same size as the Mississippi itself.  The river is named after Henry Schoolcraft, who mapped the region and discovered nearby Lake Itasca as the source of the Mississippi in 1831.  Its name in the Ojibwe language is "Ozaawindibe-ziibi" (Yellow-head River), named after Ozaawindib who guided Schoolcraft to the nearby "Omashkoozo-zaaga'igan" (Elk Lake), which Schoolcraft then named Lake Itasca.  Prior to being named for these early explorers it had been called the "Naiwa River"

Itasca: Itasca is a word coined by Henry Schoolcraft as a name for Lake Itasca, the source of the Mississippi River.  Schoolcraft coined the name from a combination of the Latin words "veritas ("truth") and caput" ("head").  The following places and ships have been named after the Mississippi Headwaters:

Schoolcraft, Michigan: Schoolcraft is a village in Kalamazoo County in the U.S. state of Michigan.  The village is located in Schoolcraft Township approximately 13 mi south of Kalamazoo on U.S. Route 131.  The population was 1,525 at the 2010 census.  The village is named in honor of geographer, geologist, and ethnologist Henry Schoolcraft.

Supporting paragraphs: Schoolcraft River Lake Itasca
Answer: Clearwater County