Generations of indigenous cultures traveled by canoe on the lakes and rivers in this area, carrying on trade across the region and continent. In the 18th century,
French voyageurs and
coureurs des bois traveled on the river to trade with the
Ojibwa and other regional Native Americans and transport furs in
canoes to major posts of French and British traders, including
Fort Detroit, built in 1701 downriver from Lake St. Clair on the Detroit River. European demand for American furs, especially
beaver, was high until the 1830s. During the mid-19th century and later,
Port Huron and
Marine City, Michigan, became major shipbuilding centers, especially the latter. Lumber harvested on
The Thumb of Michigan was shipped downriver as log rafts to
Detroit for processing and export both domestically and internationally. The wooden ships built along the river carried migrants and immigrants up the river and west through the upper Great Lakes on their way to new homes in the American West. Their farms later shipped out grain to eastern markets as part of the developing area. Beginning in the late 19th century, iron ore mined in the Mesabi Range, copper and grain were carried east through the lakes by
lake freighters, increasingly made of steel in the 20th century, traveled throughout the Great Lakes, transporting commodities such as
iron ore from the
Mesabi Range,
copper, and
grain, all products of settlers' labor. Iron was taken to
Ashtabula, Ohio and other industrial cities for processing and
steel manufacture, and grain was often shipped through to major eastern markets such as
Cleveland and
New York City. From the late 19th century, lake steamers carried passengers and traveled among the small towns along the St. Clair and
Detroit rivers, and around the Great Lakes. At one time 31 lines operated, but with the rise of automobile use in the 20th century, they gradually declined. ==Watersheds==