John Penn Arndt (November 25, 1780 – June 10, 1861) was an American merchant, pioneer, and legislator.
Born in Durham, Pennsylvania, Arndt built Durham boats with his family near Wilkes-Barre, Pennsylvania.
He moved to Buffalo, New York, and then to Mackinac Island in Michigan Territory.
In 1824, Arndt moved to Green Bay, Michigan Territory and then opened a saw mill in present-day Oconto County, Wisconsin in 1827.
Arndt was a merchant, fur trapper, owned a ferry, and was an inn keeper.
Arndt served in the first Wisconsin Territorial Council 1836-1838, of the Wisconsin Territorial Legislature.