High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Petersburg is a small unincorporated community in southeastern Springfield Township, Mahoning County, Ohio, United States. It is part of the Youngstown-Warren-Boardman, OH-PA Metropolitan Statistical Area. The community was founded in the 1790s by German immigrants from Pennsylvania. Including those from Pennsylvania was Peter Musser, Israel Warner and family who are now buried outside of Petersburg in the Old Springfield Township Cemetery along with the Rudesil family and other early families.