How do i find my old national bank account number? Within Online Banking, your full account number can be found on an eStatement or image of a cleared check. Your account number can also be found on a mailed statement from Old National Bank, on the bottom of a check or by visiting any Old National banking center. The Routing Number for Old National Bank is 086300012.How do i change my address with old national online banking? Download a Personal Address Change Form or Business Address Change Form that you can mail to Old National. For Health Savings Accounts, download an HSA Address Change Form that you can mail or fax to Old National. Within Online Banking, go to My Settings and click Edit next to either your phone number or email address to update this information.How do i contact old second national bank? You can also contact the bank by calling the branch phone number at 630-892-0202 Old Second National Bank Main Office branch operates as a full service brick and mortar office. For lobby hours, drive-up hours and online banking services please visit the official website of the bank at www.oldsecond.com.What is the routing number for old national bank? The Routing Number for Old National Bank is 086300012, as shown on the sample check below.