[1] This was the first season the club operated under the "Penn FC" name, having re-branded from the Harrisburg City Islanders in November 2017.

[2] In October 2018, the club announced that it would not play in the USL's top flight beyond that season.

Penn FC will suspend professional operations for the 2019 season and resume play in 2020 as a member of USL League One, a third-level league to be launched in 2019 by the USL parent organization.

[3] The 2018 USL season will be contested by 33 teams, 16 of which compete in the league's Eastern Conference.

At the conclusion of the regular season, the top eight teams from each conference advance to the 2018 USL Playoffs for a chance to compete for the USL Championship Title.