The Internal Revenue Service (IRS) is responsible for the determination, assessment, and collection of internal revenue in the United States. This revenue consists of personal and corporate income taxes, excise, estate, and gift taxes, as well as employment taxes for the nation�s Social Security system.
The Bureau of Internal Revenue was established July 1, 1862, to collect the new income tax, which was used to pay for the Civil War. The income tax, which was declared unconstitutional by the Supreme Court in 1895, was reinstated by the Sixteenth Amendment to the Constitution on February 25, 1913. The Bureau of Internal Revenue was responsible for enforcement of the Prohibition amendment in the 1920s.
Taxpayers queue up to pay the first national income tax in 1862,
which was levied to finance the Civil War. The Internal Revenue Service
is now the largest Treasury bureau. (Library of Congress)
The Bureau of Internal Revenue was reorganized in 1953 and renamed the Internal Revenue Service. It remains the largest of the Treasury bureaus, employing 110,000 workers nationally.