Sceptridium oneidense has broadly triangular blades, borne near the ground. The pinnules are blunt at the tip and the margins are finely or bluntly toothed. See a discussion of similar species under S. multifidum.

Sceptridium oneidense is found across the northeastern U.S., ranging west barely through Wisconsin into Eastern Minnesota. It is rare in Wisconsin where it is listed as a "special concern" species. Most confirmed reports are from the northern half of the state in moist forests with full or nearly full canopy.