Usually in dry upland forests, with oaks, but sometimes in lowland forests. The Benzie Co. record is of plants seeding in from planted trees; the origin of the Round Island tree, from the "high beach," is uncertain, but probably not a native occurrence. The only mainland Upper Peninsula record, from Delta Co., collected by J. J. Durbin and D. McNamee in 2007, however, appears to be a natural occurrence.

Carya ovata is very variable, particularly in size of fruit and in amount of pubescence on leaves and young twigs. The characteristic subapical tufts of hairs on the teeth of the leaflets are distinctive in this species; if searching on an old worn leaf in the fall reveals one or two teeth bearing a tuft the identification is positive. Very rarely there may be 7 leaflets rather than the usual 5.

The large loose elongate plates of bark characteristic of this species (and C. laciniosa) are best developed on older trees. Young trees may have smooth tight bark (as on one 1-2 dm in diameter, bearing large fruit, discovered by E. E. Sherff in Barry Co.). The husks may be slightly ridged along the sutures, but not so prominently as in bitternut.