When was the IRS started?

The IRS started during the Civil War. However the name used was not the IRS at the time. In July 1862, President Lincoln and Congress created the office of Commissioner of Internal Revenue, the Revenue Act of 1862.

In 1929, the Bureau of Internal Revenue began using the name Internal Revenue Service on tax forms. However, the name IRS was not formalized until 1953 in Treasury Decision 6038.