High Quality Content by WIKIPEDIA articles! The Chicago Federal Building in Chicago, Illinois was constructed between 1898 and 1905 for the purpose of housing the midwest`s federal courts, main post office, and other government bureaus. It stood in The Loop neighborhood on a block bounded by Dearborn, Adams and Clark Streets and Jackson Boulevard. The site held an 1880 post office, courthouse and customhouse which was cleared to make way for the new building.