WASHINGTON (AP) - Deadline filers don't need to panic if they haven't submitted their 2011 federal income tax returns yet.
This year's deadline is April 17.
Two quirks of the calendar account for the extra filing time.
April 15 fell on a Sunday this year, and Monday is Emancipation Day.
Emancipation Day marks the occasion when President Abraham Lincoln signed a law ending slavery in the District of Columbia.
Lincoln signed it April 16, 1862, more than eight months before he signed the Emancipation Proclamation, which eventually led to all slaves being freed.
Emancipation day is observed in the District of Columbia and by federal law, D.C. holidays affect tax deadlines the same way federal holidays do, giving taxpayers an extra day.
Not all the states mirror the federal deadline exactly. So, taxpayers need to double check their state deadlines.
The Associated Press