First Midwest Bancorp, Inc., headquartered in Chicago, Illinois and the parent company of First Midwest Bank, today announced that it has entered into a definitive agreement to acquire Northern States Financial Corporation, the holding company for NorStates Bank, based in Waukegan, Illinois. The financial terms of the deal are undisclosed. NorStates Bank operates eight offices in Lake County, Illinois and has approximately $500 million in total assets, $400 million in deposits, of which 90% are core deposits, and $320 million in loans.