Kleinfeltersville is an unincorporated community in Heidelberg Township, Lebanon County, Pennsylvania, United States. It is almost due east of Schaefferstown on Pennsylvania Route 897.
Kleinfeltersville is one of the longest one-word, unhyphenated place names in the United States recognized by the U.S. Board on Geographic Names. At 17 characters, it is tied with Mooselookmeguntic, Maine. Kleinfeltersville (ZIP code 17039) is the longest one-word name given to a United States Post Office.
It is the site of the Kleinfeltersville Hotel and Tavern, built before the start of the American Civil War and is also known to outdoorspersons as the community nearest to the Middle Creek Wildlife Management Area, a popular location for birdwatching and other outdoor activities.