E. eocenica is known from fossil fruits found in the middle Eocene Claiborne Formation deposits of the southeastern United States.

E. eocenica is one of five described fossil species from North America assigned to the modern genus Eucommia.

[1] Eucommia eocenica is known from a number of specimens recovered from Claiborne Formation fossil sites in Tennessee, Missouri, and Mississippi.

Two fossils of the species were first described by Edward W. Berry in 1930 from the Holly Hills sand of Tennessee as Carpolithus banisteroides and Simaroubites eocenica respectively.

In their reexamination they noted that the species Leguminosites copaiferanus which was also described by Berry in 1930 is likely also a E. eocenica fruit rather than a separate taxon.