BATON ROUGE - Millions of taxpayers are expected to file for their tax returns or ask for a six-month extension on Monday.

The deadline was extended from Friday, April 15 to Monday, April 18th because Emancipation Day was observed in the District of Columbia. The D.C. legal holiday commemorated the President Abraham Lincoln's signing the Emancipation Act that freed slaved in the area.

Residents in flood-affected areas are eligible for filing extensions. That includes residents in Livingston, Ascension and St. Helena parishes. 

The Internal Revenue Service has $1 billion in unclaimed refunds. Taxpayers can claim their refunds from up to three years ago.

The penalties for non-filing or filing late are greater than late payment penalties. The deadline to file taxes is Monday at midnight.

More than 150 million tax returns are expected to be filed in 2016. As of April 8, almost 82 million refunds had already been issued. According to the IRS, the average refund amount was $2,798.