Sheppard & Myers Shoe Company (Hanover Shoe Company) expanded rapidly in the early 1900's with seven factories and several hundred company stores throughout eastern U.S., becoming Hanover's largest manufacturer.
From the early 1900's, Hanover Wire Company became a world-wide leader in making wire cloth, Hanover Cordage Company produced large quantities of twine and other cordage, and R.H. Sheppard Company is internationally famous for its production of power steering equipment for heavy vehicles. The R.H. Sheppard Company provides about 50% of all heavy-duty power steering units used in the U.S. plus a significant share of the international market.
Snack and other food production contributed significantly to Hanover becoming one of the major manufacturing centers in the state, especially Hanover Canning Company, later Hanover Foods, Inc. (vegetables), Utz Quality Foods (potato chips), and Snyder's of Hanover (pretzels).
Mail order businesses also thrived. After World War II, Lana Lobell Company (later Hanover House Industries) grew in size until it distributed over 60,000,000 catalogs a year. Everybody's Poultry magazine, now Sheridan Press, and Doubleday Books built large publication centers here. For a time Hanover had the sixth largest postal volume in Pennsylvania.