Oak-hickory-pine (Quercus-Carya-Pinus) forests of Hot Springs National Park in the Ouachita Mountains of Arkansas were analyzed and their composition compared with other forests in the Ouachitas, with forests of the mountains of the Arkansas Valley Region, and with oak-hickory-pine forests of the Piedmont east of the Mississippi River. In Hot Springs National Park, abundant Pinus echinata forms a background against which the abundances of hardwood species vary. DCA and CCA ordinations revealed that the abundances of hardwood species (but not pine) were strongly related to aspect and topography, with Quercus marilandica, Q. stellata, Carya texana, and the normally mesophytic Carya cordiformis abundant on southerly and southeasterly exposures; with other oaks (Quercus alba most important, but also Q. velutina, Q. falcata, Q. rubra) and mockernut hickory (Carya tomentosa) most abundant on nearly level terrain or less xeric directions of exposure; and with Liquidambar styraciflua and other more mesophytic non-oak species most abundant in ravines and along streams, where soils also had higher Na and Ca values. Hot Springs National Park forests were quite similar to those of other sites in the Ouachita Mountains, though with much less Quercus shumardii than has been reported in the western Ouachitas. Ouachita Mountain oak-hickory-pine forests are much like those of the Piedmont of the eastern United States, but differ from the latter in the presence and high abundance of Carya texana, which does not occur east of the Appalachians, and in lacking Liriodendron tulipifera and Quercus prinus, neither of which ranges as far west as the Ouachitas. The information in this article is offered as a partial remedy for the omission of that portion of the Oak-Hickory-Pine Forest Region west of the Mississippi from the most recent major treatment by Martin, Boyce, and Echternacht of the vegetation of the southeastern United States.