The exact date of the formation of Fairfield Township is not known, but court records point to sometime between August 1825 and December 1826.

[4] John Andrew Shulze retired to Fairfield Township following his 1823–1829 term as governor of Pennsylvania.

Shulze bought 500 acres (2.0 km2) in western Fairfield Township, now part of Montoursville, for $12,000.

His plan was to spend his retirement farming in the West Branch Susquehanna Valley.

He built a brick house on his farm and donated an acre of land for the construction of Union Church, which was shared by the Lutheran and Presbyterian congregations of Montoursville and Fairfield Township.

Governor Shulze then took up residence in Montoursville, lost even more lawsuits and eventually moved to Lancaster in 1846, where he lived until his death in 1852.

Fairfield Township has many residential neighborhoods that are contiguous with the neighboring borough of Montoursville.

PA 87 runs through the northwestern part of the township, leading northeastward up the Loyalsock Creek valley 30 miles (48 km) to Forksville.