LaSalle Street is a major north-south street in Chicago named for René-Robert Cavelier, Sieur de La Salle, a 17th century French explorer of the Illinois Country. The portion that runs through the Chicago Loop is considered to be Chicago's financial district.

René-Robert Cavelier, Sieur de La Salle, was a 17th-century French explorer and fur trader in North America. He explored the Great Lakes region of the United States and Canada, and the Mississippi River. He is best known for an early 1682 expedition in which he canoed the lower Mississippi River from the mouth of the Illinois River to the Gulf of Mexico; there, on 9 April 1682, he claimed the Mississippi River basin for France after giving it the name La Louisiane. One source states that "he acquired for France the most fertile half of the North American continent". A later ill-fated expedition to the Gulf coast of Mexico gave the United States a claim to Texas in the purchase of the Louisiana Territory from France in 1803. La Salle was assassinated in 1687 during that expedition.