If you're filing your taxes the by mail, Chicago's main post office downtown at Harrison and Canal is expanding its hours to accommodate taxpayers.
The office will stay open until midnight to collect last-minute tax returns. Collectors will line the streets at Harrison and Canal to grab returns from last-minute filers.
All other Chicago-area post offices are set to close at their normal times.
The Chicago-district postmaster, Karen Schenck, says one of the most common mistakes people make is not including enough postage on envelops with their returns.
Those envelops will be returned and those taxpayers will be considered late filers.
(The Associated Press contributed to this report.)