Since 1955, for those living in the United States, Tax Day has typically fallen on April 15. For people who file a U.S. tax return and live outside the United States and Puerto Rico, Tax Day has typically fallen on June 15, because of the two-month automatic extension granted to filers by IRS Publication 54.
Emancipation Day, a holiday in Washington, D.C. commemorating the emancipation in April 1862 of enslaved people of African descent and which is observed on the weekday closest to April 16, causes special rules to apply: when April 15 falls on a Friday, tax returns are due the following Monday; when April 15 falls on a Saturday or Sunday, tax returns are due the following Tuesday.
Federal income tax was introduced with the Revenue Act of 1861 to help fund the Civil War, and subsequently repealed, re-adopted, and held unconstitutional.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 filing deadline for U.S. federal income tax returns for individuals remains April 15 or, in the event that the 15th falls on a Saturday, Sunday or holiday, the first succeeding day that is not a Saturday, Sunday or holiday.