This is a hard question to answer as income tax came in stages. According to Tax.org, the first federal income tax was not the Internal Revenue Act of 1862. August 5, 1861 was the date of the very first imposition of income tax in the US. The goal was to help fund the US government Civil War effort. It was part of the Revenue Act of 1861. Read this segment taken from http://www.tax.org/Museum/1861-1865.htm: "The first federal income tax in American history actually preceded the Internal Revenue Act of 1862. Passed in August 1861, it had helped assure the financial community that the government would have a reliable source of income to pay the interest on war bonds." **Look Up: I clearly stated where the quote came from**

1862. In 1862, in order to support the Civil War effort, Congress enacted the nation's first income tax law. It was a forerunner of our modern income tax in that it was based on the principles of graduated, or progressive, taxation and of withholding income at the source. During the Civil War, a person earning from $600 to $10,000 per year paid tax at the rate of 3%. Those with incomes of more than $10,000 paid taxes at a higher rate. Additional sales and excise taxes were added, and an “inheritance” tax also made its debut. In 1866, internal revenue collections reached their highest point in the nation's 90-year history—more than $310 million, an amount not reached again until 1911. The Act of 1862 established the office of Commissioner of Internal Revenue. The Commissioner was given the power to assess, levy, and collect taxes, and the right to enforce the tax laws through seizure of property and income and through prosecution. The powers and authority remain very much the same today. ********************** The first federal income tax was imposed by Congress in 1862, to finance the Union's waging of the Civil War. It levied a 3% tax on incomes above $600, rising to 5% for incomes above $10,000. Rates were raised in 1864. The Civil War income tax was repealed in 1872, but a new income tax was enacted in the late 1800s. [1] However, the Supreme Court struck down the income tax in 1895. It ruled that the portion of the income tax that applied to income on property was a direct tax that, under the US Constitution, could not be levied without apportioning the tax by population. Resources: http://www.infoplease.com/ipa/A0005921.html http://www.answers.com/topic/taxation-in-the-united-states

Income tax first appeared in the United States in 1862, during the Civil War. At that time only about one percent of the population was required to pay the tax. A flat-rate income tax was imposed in 1867. The income tax was repealed in its entirety in 1872. Income tax was a rallying point for the Populist party in 1892, and had enough support two years later that Congress passed the Income Tax Act of 1894. The tax at that time was two percent on individual incomes in excess of $4,000, which meant that it reached only the wealthiest members of the population. The Supreme Court struck down the tax, holding that it violated the constitutional requirement that direct taxes be apportioned among the states by population (Pollock v. Farmers' Loan & Trust, 158 U.S. 601, 15 S. Ct. 912, 39 L. Ed. 1108 [1895]). After many years of debate and compromise, the Sixteenth Amendment Constitution was ratified in 1913, providing Congress with the power to lay and collect taxes on income without apportionment among the states. The objectives of the income tax were the equitable distribution of the tax burden and the raising of revenue. Since 1913 the U.S. income tax system has become very complex. In 1913 the income tax laws were contained in eighteen pages of legislation; the explanation of the Tax Reform Act of 1986 was more than thirteen hundred pages long (Pub. L. 99-514, Oct. 22, 1986, 100 Stat. 2085). Commerce Clearing House, a publisher of tax information, released a version of the Internal Revenue Code in the early 1990s that was four times thicker than its version in 1953. Changes to the tax laws often reflect the times. The flat tax of 1913 was later replaced with a graduated tax. After the United States entered World War I, the War Revenue Act of 1917 imposed a maximum tax rate for individuals of 67 percent, compared with a rate of 13 percent in 1916. In 1924 Secretary of the Treasury Andrew W. Mellon, speaking to Congress about the high level of taxation, stated, The present system is a failure. It was an emergency measure, adopted under the pressure of war necessity and not to be counted upon as a permanent part of our revenue structure… . The high rates put pressure on taxpayers to reduce their taxable income, tend to destroy individual initiative and enterprise, and seriously impede the development of productive business… . Ways will always be found to avoid taxes so destructive in their nature, and the only way to save the situation is to put the taxes on a reasonable basis that will permit business to go on and industry to develop. Consequently, the Revenue Act of 1924 reduced the maximum individual tax rate to 43 percent (Revenue Acts, June 2, 1924, ch. 234, 43 Stat. 253). In 1926 the rate was further reduced to 25 percent. http://www.answers.com/topic/income-tax