You can thank President Abraham Lincoln for the extra time in filing your taxes this year. Taxes aren't due until tomorrow.  April 15 was on a Sunday this year and today is Emancipation Day. This is a federal holiday observed in D.C. effecting the tax deadline. It's the marks the day when President Lincoln signed the law that ended slavery in the District of Columbia. That was some 8 months before he signed the Emancipation Proclamation that lead to all slaves being freed.