The Expeditions of René-Robert Cavelier, Sieur de La Salle were a series of trips into the Mississippi and Ohio Valley by French explorers led by René-Robert Cavelier, Sieur de La Salle that began in the late 1660s and continued for two decades. Much of the area that was explored was land that no European had ever ventured into. The expeditions led to the establishment of an overland trade route connecting French colonies in Canada with French colonies in Louisiana. All of the land covered in the expedition was claimed on behalf of Louis XIV, King of France, and initiated a period of French control in the region that would last for nearly a century.
René-Robert Cavelier, Sieur de La Salle arrived in New France in 1666. He was the son of a wealthy merchant family from Rouen, France and came to the New World to set up trade with Native American populations. He went immediately to Montreal, which was then the furthest inland post the French controlled. At that time, the post was little more than a mission where his brother served as a Jesuit priest who was working to convert the local Huron to Christianity. At that time, the region was in the height of the Beaver Wars, a brutal conflict between the French-backed Algonquian tribes fighting against the English-supported Iroquois Confederacy.
La Salle purchased a large tract of land near modern Lachine, Quebec. There he set up a thriving trading post, purchasing furs from the local tribes and serving as a middleman, selling the furs to European merchants who transported them back to France. From Seneca traders, La Salle first learned of the Ohio country and that a river flowed from there all the way to a great sea. The possibility of such a river intrigued La Salle because of its obvious value to trade. If such a route existed, it would make trading trips deep into the interior of North America possible and much easier than overland routes. If discovered, the trade from such a route could also be very lucrative. At the time, most Europeans, having no clear idea of the actual size of North America west of the Appalachians, still thought that they were very near the source of the Asian spices, and La Salle thought that perhaps this route would lead to India.