Kleinfeltersville is an unincorporated community in Heidelberg Township, Lebanon County, Pennsylvania, United States.

[2] Kleinfeltersville (ZIP code 17039) is the longest one-word name given to a United States Post Office.

It is also known to outdoorsmen as the community nearest to the Middle Creek Wildlife Management Area, a popular location for birdwatching and other outdoor activities.

The village of Kleinfeltersville itself has a background steeped in religious history as it is the center of the founding of the Evangelical Association (a German expression of Methodism) by Jacob Albright.

It is rumored, according to the 1892 guest ledger of the hotel that Grover Cleveland and Adlai Stevenson spent time here just 11 days prior to their election on November 8, 1892.