The company was started by John S. Lapp in 1916. He had previously worked at Locke in Victor, NY and for Fred Locke. The Le Roy plant was a manufacturer of wet process porcelain insulators at 130 Gilbert St. In 1957, they ceased manufacture of unipart pin-type insulators and abandoned multipart pin-type insulators a few years later. In February 2005, production of porcelain line posts and station post insulators was transferred to the Le Roy plant. In December 2005, Lapp was purchased by a group of German investors. The new owners are Andlinger Company, Inc. The new company name is Lapp Insulator Co. LLC.