For the most part, Silurian trilobites from Ohio have been poorly documented. This paper records taxa from the Niagaran Series. Specimens discussed here were collected from the southern and west-central areas of the state. Species reported here are Arctinurus boltoni (which is questionably recorded from Ohio), Bumastus insignis, Cheirurus niagarensis, Flexicalymene celebra, Sphaerexochus romingeri, Trimerus delphinocephalus, Dalmanites brevicaudatus, and Dalmanites platycaudatus. One species of Calymene is left in open nomenclature. During the deposition of the Niagaran in Ohio, trilobites lived in a variety of shallow marine environments, although most are associated with reef, inter-reef, and reef-flank lithofacies.No embarg