Many of the more than 11 million taxpayers who requested an automatic six-month extension this year have yet to pay. IRS Spokesperson, Karen Connelly says there may be as many as 22,400 Wyoming tax payers whose returns and tax payments are due on Monday.

Connelly suggests before filing, to check if your qualified for any of the often-overlooked credits and deductions. "And its easy if you use IRS e-File or the Free-File systems. Both of those are available through October 15th as well."

For most, Monday the 15th is the last day, though, some still have more time, including members of the military who have at least 180 days after they leave a combat zone to both file returns and pay any taxes due.

Some helpful links:

often-overlooked credits and deductions <>: