<P> Taxation of income in the United States has been practised since colonial times . Some southern states imposed their own taxes on income from property , both before and after Independence . The Constitution empowered the federal government to raise taxes at a uniform rate throughout the nation , and required that `` direct taxes '' be imposed only in proportion to the Census population of each state . Federal income tax was first introduced under the Revenue Act of 1861 to help pay for the Civil War . It was renewed in later years and reformed in 1894 in the form of the Wilson - Gorman tariff . </P>
the first time the united states enacted a temporary income tax was
first introduced under the Revenue Act of 1861 to help pay for the Civil War