Security National Bank Address: 901 Pierce St, Sioux City, IA 51101 Phone: (712) 277-6638 Hours: Mon: 9am-6pm Tue: 9am-6pm Wed: 9am-6pm Thu: 9am-6pm Fri: 9am-6pm Sat: 9am-12pm Banks Other Businesses: First American Bank at 800 Gordon Dr, Sioux City, IA 51101 Great Southern Bank at 329 Pierce St, Sioux City, IA 51101 Morgan Stanley at 600 4th Street, Sioux City, IA 51101 Northwest Bank at 818 W 7th St, Sioux City, IA 51103 Heritage Bank NA at 505 5th St, Sioux City, IA 51101