A novel inbred maize line designated PH8TN and seed, plants and plant parts thereof. Methods for producing a maize plant that comprise crossing inbred maize line PH8TN with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into PH8TN through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. Hybrid maize seed, plant or plant part produced by crossing the inbred line PH8TN or an introgressed trait conversion of PH8TN with another maize line. Inbred maize lines derived from inbred maize line PH8TN, methods for producing other inbred maize lines derived from inbred maize line PH8TN and the inbred maize lines and their parts derived by the use of those methods.