The fur company's men so liked the Mackinaw boat that when asked to build, paddle, and pole light cargo boats up the Missouri River to the company's new trading region in Dakota Territory and Montana Territory, they called the boats "mackinaws", even though it was comparatively difficult to move a boat up the Missouri River by sail power. The Missouri River "mackinaw" may have borne some similarities to the river pirogue developed by French colonists in Louisiana Territory and adapted by the Americans as early as the time of Lewis and Clark.