The Federal Reserve Bank of Chicago (informally the Chicago Fed) is one of twelve regional Reserve Banks that, along with the Board of Governors in Washington, D.C., make up the nation's central bank. The Chicago Reserve Bank serves the Seventh Federal Reserve District, which encompasses the northern portions of Illinois and Indiana, southern Wisconsin, the Lower Peninsula of Michigan, and the state of Iowa. In addition to participation in the formulation of monetary policy, each Reserve Bank supervises member banks and bank holding companies, provides financial services to depository institutions and the U.S. government, and monitors economic conditions in its District.

en.wikipedia.org/wiki/Federal_Reserve_Bank_of_Chicago