The Rapp surname appears to be Germanic. A well-known Rapp was George Rapp who led a splinter group of Lutherans from Germany to Pennsylvania in 1805. They became a Utopian sect known as the Rappites. In 1815 100 of them floated down the Ohio and settled on the lower Wabash, a community they called Harmonie. In 1825 they sold their Utopian community and returned to Pennsylvania.

Later the community was settled by another Utopian sect and called New Harmony.

Jennifer