The most recent checklist of Pennsylvania mosses credits the Commonwealth with 443 taxa. In that list Montour County, the smallest county in Pennsylvania, has 19 mosses attributed to it. The most recent account of the liverworts and hornworts of Pennsylvania lists 147 taxa from the Commonwealth, but only five liverworts from Montour County. As a result of recent fieldwork in Montour County, an additional 45 moss and 2 liverwort species have been found in the county. New county mosses of interest include Brachythecium falcatum, Helodium elodioides, Lindbergia brachyptera, Syntrichia papillosa, and S. ruralis. In addition, six mosses previously known from Montour County only in literature reports were collected. Voucher specimens for all bryophytes reported here are deposited in MO. Currently, 64 moss and 7 liverwort taxa have been verified or reported in the literature from Montour County.