HAMM, a town in the Prussian province of Westphalia, on the Lippe, 19 m. by rail N.E. from Dortmund on the main line Cologne-Hanover. Pop. 3) 53,527. Hamm, which became a town about the end of the 12th century, was fortified in 1226, and became a member of the Hanseatic League. In 1666 it came into the possession of Brandenburg, and in 1763 its fortifications were dismantled. The town possesses very extensive wire factories and machine works, breweries and manufactories of brushes, baskets, leather, starch, varnish and oil. Nearby are some thermal baths, and coal mines.