Question

When and why was the first U.S. income tax introduced?

Answer 1

The U.S. first ratified tax on February 3,1913. 

Answer 2

If, in the midst of sorting receipts and studying the latest changes in the US income tax laws, you suddenly wonder "What is the origin of this annual ritual in the weeks leading up to April 15th?" here are some places you can go for answers.

The origin of the income tax on individuals is generally cited as the passage of the 16th Amendment, passed by Congress on July 2, 1909, and ratified February 3, 1913; however, its history actually goes back even further. During the Civil War Congress passed the Revenue Act of 1861 which included a tax on personal incomes to help pay war expenses. The tax was repealed ten years later. However, in 1894 Congress enacted a flat rate Federal income tax, which was ruled unconstitutional the following year by the U.S. Supreme Court because it was a direct tax not apportioned according to the population of each state. The 16th amendment, ratified in 1913, removed this objection by allowing the Federal government to tax the income of individuals without regard to the population of each State. For additional information on taxation in the United States, see the section on taxes on the web site of the U.S. Department of the Treasury.