Applied to land features, mouth is a term for all manner of surface openings, including the crater of a volcano as well as the entrances and exits to canyons, valleys, and caves. A mouth is also the place where one waterway empties into a larger body of water, for example where a river flows into the sea. (The mouth is considered the last identifiable portion of the smaller tributary before it merges with the larger entity.) Place- names derived from mouth include the Mouth of River Styx Landing, in Mississippi County, Arkansas; and Mouth of the Maravillas, at Bourland Canyon, Texas. Other American place-names arise from two Algonquian words for mouth: sawacotuck, which means “mouth of the tidal stream,” is the basis for the name of Saugatuck, Michigan, a town located at the mouth of Kalamazoo River. Saco, the Algonquian word for “flowing out” or “river-mouth,” is the source for several town names, including Saco, Missouri; Sac City, Iowa; and Saco, Maine. Still other kindred American place-names arise from boca, the Spanish word for mouth, including the historic town of Boca, California, located at the mouth of the Little Truckee River. Based on these typical examples, it would seem likely that Boca Raton, Florida, would also be located near the mouth of a river. Yet the history of that city’s name illustrates instead the mutability of landscape language. Boca Raton and nearby Lake Boca Raton take their name from Boca Ratones, which is shown on an eighteenth-century Spanish map. This Boca Ratones, as it turns out, was merely a bay inlet, and not a mouth. Moreover, its location was nowhere near the present-day city of Boca Raton, but far to the south in Biscayne Bay near Miami. For reasons now unknown, the name migrated north up the Florida coast and was applied first to the lake (although the lake did not then have a connection to the sea) and some years later to the emerging coastal settlement of Boca Raton. During this process, citizens of the new Florida city shortened the original adjective ratones—colloquially, “thieves”—to the apparently more suitable ratón, Spanish for rat.