There are still a few weeks left to file your 2012 tax return, but April 15 of this year marks another important deadline for taxpayers: it's your last chance to file for a refund on your 2009 taxes.

Most people three years to claim their refund, and that deadline is fast approaching. If you qualify for a refund, you won't have to pay a penalty either, so it's an especially good idea. Refunds that go unclaimed after three years are deposited in the U.S. Treasury.

Nearly one million taxpayers who did not file a return in 2009 are owed nearly $1 billion in unclaimed refunds. If you did not file in either 2010 or 2011, or if you currently owe taxes exceeding what your 2009 refund would be, then you wouldn't get a refund.

You can receive all the proper forms from the IRS's website here, or by calling 800-TAX-FORM (800-829-3676). There is a full chart of how many people in each state are owed refunds, and what the average refund is in those states over at the Wall Street Journal's Total Return blog. More than 100,000 people in California, for example, have a potential average unclaimed refund of $518.

[MarketWatch, WSJ]