Income tax was first introduced in the United States of America in 1861. A rate of three percent was levied on incomes above $800 per year and the resulting revenue was used to help fund the American Civil War effort. However, income tax was seen as unconstitutional and the law was repealed in 1872. The idea of a tax on personal income, at a rate of two percent, was reintroduced in the Revenue Act of 1894, but the legal status of this kind of tax was still unclear. In 1913, the “Sixteenth Amendment” to the Constitution of the United States was ratified. This cleared the way for the modern income tax system in the USA.
The details of the income tax system have changed greatly since 1913. The top rates of tax have varied enormously and were particularly high during the First and Second World Wars and the Great Depression. Individuals and families with very low levels of income do not have to pay income tax and may receive some subsidy via the tax system.
In 1913 Tax Day, or the filing deadline, was fixed on March 1. However, it was moved to March 15 in 1918 and April 15 in 1955, where it has remained since then. If April 15 falls on a Saturday, Sunday or a civil holiday, such as Patriot’s Day, the deadline is extended to the next working day. An extension due to a holiday may only affect certain states. In 2007, the residents of some states were granted an extension due to the disruption to public life in many areas caused by a huge Nor’easter storm. In some years in Washington DC, Emancipation Day may be the reason to extend the deadline for filing an income tax return (Tax Day). In 2007, the observance Emancipation Day in Washington DC had the effect of nationally extending the 2006 income tax filing deadline from April 16 to April 17. This 2007 date change was not discovered until after many forms went to print.
For more information: https://www.timeanddate.com/holidays/us/tax-day