Clayton Mark (June 30, 1858 – July 7, 1936), one of the pioneer makers of steel pipe in the United States, was an industrialist in the Chicago area who founded the Mark Manufacturing Company in 1888, a firm for the fabrication and sale of water-well supplies and Clayton Mark and Company in 1900. In addition, Mark founded Marktown, a planned worker community in Northwest Indiana on the National Register of Historic Places. He was known for his philanthropy and civic contributions.[1]