Traditionally, Tax Day is April 15th unless that date falls on a Saturday or a Sunday, in which case the due date for federal income tax returns gets pushed ahead to the next business day. This year, however, Emancipation Day falls on a Saturday and will be observed on the preceding Friday, thus pushing the Tax Day deadline to Monday, April 18.

Since 2005, Emancipation Day has been a holiday observed in Washington DC every April 16 to recognize Abraham Lincoln’s signing of the Compensated Emancipation Act. President Lincoln signed this Act on April 16, 1862 which freed over 3,000 slaves in the Washington DC area. Almost nine months later he would sign the Emancipation Proclamation which led to the freedom of over 3 million slaves throughout the country and was the cornerstone to abolishing slavery in America.

Sources: Time and Date, Public Holidays