In Revenue Ruling 2015-13 the IRS clarifies the due date for estimated tax payments and income tax returns when the due date falls on a Saturday, Sunday, or legal holiday such as Emancipation Day or Patriots’ Day.  Emancipation Day is typically observed in DC on April 16 and Patriots’ Day is observed in Massachusetts and Maine on the third Monday of April.  When Emancipation Day falls on Saturday, the legal holiday is observed on Friday, April 15 and the individual tax return filing deadline is extended to Monday, April 18.  In such instances, the statewide observation of Patriots’ Day on April 18 would further extend the filing deadline for residents of Maine and Massachusetts to Tuesday, April 19. However, estimated tax payments still would be due on Monday, April 18 for residents of Maine and Massachusetts.