In the United States, Tax Day is the day on which individual income tax returns are due to be submitted to the federal government. Since 1955, Tax Day has typically fallen on or just after April 15. Tax Day was first introduced in 1913, when the Sixteenth Amendment was ratified. The date is delayed if it conflicts with a weekend or public holiday such as Emancipation Day. Natural disasters or public health emergencies, most recently the COVID-19 pandemic, also delay Tax Day when they prevent filing taxes on time, and state income agencies often delay their own submission deadlines to remain in common with that of the federal government. The federal government may set a different deadline for certain states, as it did when Patriots' Day conflicted. History Federal income tax was briefly introduced with the Revenue Act of 1861 to help fund the Civil War, and subsequently repealed, re-adopted, and held unconstitutional. The early taxes were based on assessments, not voluntary tax returns. Tax payment dates varied by act. The case of Pollock v. Farmers' Loan & Trust Co. challenged the constitutionality of the Wilson–Gorman Tariff Act of 1894, which taxed incomes over $4,000 at the rate of two percent. The case was decided by the United States Supreme Court in 1895. The Supreme Court decided that the Act's unapportioned income taxes on interest, dividends, and rents were effectively direct taxes. The Act was therefore unconstitutional because it violated the Constitution's rule that direct taxes be apportioned among the states. In 1913, eighteen years later, the Sixteenth Amendment to the United States Constitution was ratified. This Amendment gave the United States Congress the legal authority to tax all incomes without regard to the apportionment requirement. The filing deadline for individuals was March 1 in 1913 (the first year of a federal income tax), and was changed to March 15 in 1918 and again to April 15 in 1955. Today, the deadline remains April 15, unless it conflicts with on a weekend or a holiday. Alignment with state and District of Columbia holidays and changes in date Tax Day occasionally falls on Patriots' Day, a civic holiday in the Commonwealth of Massachusetts and state of Maine, or the preceding weekend. When this occurred for some time, the federal tax deadline was extended by a day for the residents of Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont, and the District