Normally, people associate April 15 with the deadline for filing individual tax returns.
However, this is not always the case.
In 2016, April 15 is a holiday in Washington DC. Emancipation Day is a legal holiday in DC and is observed on April 16 every year. Since April 16 falls on a Saturday in 2016, it is celebrated on the closest weekday, which is Friday April 15.
As such, the filing deadline for 2016 has been pushed back to the next business day, which is Monday April 18.
If you are planning to file an extension, the deadline to file your tax return is October 17. Nonetheless, you will still need to pay any taxes due on April 18.