The IRS said Wednesday that taxpayers will have two extra days this year to file their 2011 returns.

The April 17 deadline this year comes via two quirks of the calendar.  The standard tax filing day of April 15 falls on a Sunday this year, so the date would be moved to April 16. But that day is Emancipation Day, a legal holiday in the District of Columbia.

The holiday celebrates the day in 1862 when President Lincoln signed the Compensated Emancipation Act, which freed about 3,100  slaves in the district.  Under federal law, D.C. holidays affect tax deadlines, just like federal holidays do, thus taxpayers get an extra day.