Where do black walnut trees grow?

Context: Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.

Answer: North America from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas.