Where is the Northern Trust bank headquarters?

1st Trust Bank, Inc. 3 Alliance Community Bank 5 American Continental Bank 6 AMERICAN PLUS Bank National Association 6 BANK INDEP 2 BANK OF BIRD-IN-HAND 4 BLACKHAWK B&T 5 CITIZENS Community FED National Association 11 Clinton National Bank 9 Cottonport Bank 5 Farmers & Drovers Bank 4 Farmers & Merchants National Bank 1 FIELD & MAIN Bank 5 First National Bank of Louisiana 6 FNB Bank, Inc. 5 State Bank Financial 5 State Bank of Graymont 13 Tandem Bank 11 TrustBank 9 Valley Bank of Ronan 3