Des Plaines River - Etymology

Etymology

The Des Plaines River was named by early French Voyageurs or coureur de bois sometime between the 17th and 18th centuries, after the trees lining the banks of the river.

The word la plaine, in the 18th century Mississippi Valley dialect of French spoken by the Frenchmen at the time, actually referred to either the American sycamore or the red maple, both of which resembled the European plane tree either in their palmate leaves or their similar bark.

The English word for the plane tree actually came from the 14th century Old French word la plane. However, since the 18th century, the French word for the plane tree has transformed into le platane. As the Latin name for the plane tree is platanus, this transformation was likely done as a part of the attempts of late 18th century French academics to change the spelling of many French words to what was perceived as their Latin origins. A side effect of this was the obscuring of the original French meaning of the name given for the Des Plaines River. Today, des Plaines in modern Parisian French now literally means "of the plains" or "of the prairie". This has led to some confusion about the meaning of the original French name for the Des Plaines River.

Many people today believe that the river was named after the plains and prairies through which the river flows. However, in the 18th century French dialect of the time, it was much more common to use the word "prairie" to indicate a plain, such as Prairie du Rocher and Prairie du Chien. Also, it is much more likely that the river was named in reference to the trees rather than the land, because the French at the time traveled nearly all the time by the river, and the view of the prairie supposedly referenced was nearly always blocked by trees. To this day a large number of both maples and sycamores grow along the Des Plaines River.

Although the original French name for the river has survived, its pronunciation has been altered. Today, it is pronounced in an anglicized way by locals (roughly "dess plains"), rather than according to the French pronunciation.