List of GNB Bank Stores in Marshalltown, IA Outlet Note Regular Brands GNB Bank Iowa Marshalltown Rating 4.7 based on 54 votes Official Website http://gnbbank.com Products Online Banking Credit Cards Insurance Savings Investments Saving Bank Saving Plans NameAddressPhone Name/Address/Phone GNB Bank outlet - Marshalltown 2504 S 2nd St (641) 753-4040 People Also Viewed