The area of convergence of the three rivers Arkansas, Verdigris and Neosho is called "Three Forks."

In Oklahoma the Neosho ends at its confluence with Spring River at the Twin Bridges Area at Grand Lake State Park.

[6] In Oklahoma, Pensacola Dam at Langley forms the Neosho's largest reservoir, the Grand Lake o' the Cherokees.

Robert S. Kerr Dam near Locust Grove forms Lake Hudson, (also known as Markham Ferry Reservoir), and a dam upstream of Fort Gibson forms Fort Gibson Lake.

In Kansas, the Neosho is joined by the Cottonwood River in Lyon County.