WASHINGTON (AP) — Millions of taxpayers face a midnight deadline Monday to file their tax returns, while millions of others will ask for more time —a six-month extension.

There was a three-day delay beyond the traditional April 15 deadline Friday was a legal holiday in the District of Columbia. It was Emancipation Day, which commemorates President Abraham Lincoln’s signing of an act that freed more than 3,000 enslaved people in the district and compensated their owners.

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

The IRS reminds taxpayers that filing extensions grant more time to file returns, but don’t extend time to pay.