The Great Raft was a gigantic logjam or series of "rafts" that clogged the Red River and was unique in North America. It probably began forming around 1100–1200 AD.

The Great Raft grew faster at its upper end than the lower end decayed or washed out, leading to its peak length spanning more than 160 miles in the early 1830s. Steamboat builder and river captain Henry Miller Shreve (1785–1851) began systematically removing the Great Raft, a task that was continued by others until the latter part of the 19th century. For his efforts the city of Shreveport, Louisiana, was named after him.