Great Miami River or Miami (mei-AM-uh, -ee), river, c.160 mi/257 km long, formed in W Ohio near Indian L. and flowing generally SW past Dayton to the Ohio R. at the Ind. state line; 39°06'N 84°48'W. The Miami R. system has large-scale flood-control projects. The Miami and Erie Canal (c.240 mi/386 km long; opened in the 1830s) linked the upper Miami R. with L. Erie and was the principal transportation route of W Ohio until the 1850s. The Little Miami R. (95 mi/153 km long) to the E and generally parallel, rises SE of Springfield and enters the Ohio R. at Cincinnati.
