Also serving the greater Mendota area is Sts. Peter and Paul Catholic Church in Peterstown, a small community with a mostly German Catholic background.  The parish itself was founded in 1853 and a church built to serve the farmers in the area.  After several frame structures were lost to fire, it was decided to build a church using limestone.  The material was quarried in the nearby town of Troy Grove.  The church, which stands on the site today, was completed in 1872.

The parish campus includes a school, in operation from 1917 - 1976, a rectory constructed in 1918, a parish hall raised in the 1950's, and a cemetery.  Today, the Peterstown school is used as a TEC (Teens Encounter Christ) center and the rectory converted to accomodate Cursillo, the adult version of TEC.

Today, Sts. Peter and Paul Parish has approximately 70 member families.