The IRS began in 1862 as a temporary Civil War tax agency

The Internal Revenue Service did not exist for the first 73 years of the United States. The federal government collected tariffs and excise taxes, but had no permanent income tax or central tax collection agency. When the Civil War began in 1861, the government needed money fast. Congress created the Office of Internal Revenue in 1862 as a temporary measure to collect an income tax on wages and profits to fund the war effort.

That temporary office became permanent. After the Civil War ended in 1865, Congress kept the income tax and the agency that collected it. The office was renamed the Bureau of Internal Revenue in 1869. For the next 25 years, it collected income tax from individuals and businesses, though the tax itself was repealed in 1872, reinstated in 1894, and then struck down by the Supreme Court in 1895 as unconstitutional.

Key Takeaways

  • The IRS started as the Office of Internal Revenue in 1862 during the Civil War to collect income tax for war funding.
  • The agency became permanent after the war ended, even though the income tax itself was repealed, reinstated, and ruled unconstitutional multiple times between 1872 and 1895.
  • The 16th Amendment, ratified in 1913, made federal income tax constitutional and gave the IRS a permanent role in American government.
  • The IRS took its current name in 1953 and has grown from a small wartime office into a major federal agency with regional offices across the country.

The 16th Amendment made income tax permanent in 1913

The Supreme Court's 1895 decision left Congress unable to collect income tax without amending the Constitution. In 1909, Congress proposed the 16th Amendment, which gave the federal government the power to collect income tax without apportioning it among the states. The amendment was ratified on February 3, 1913, and when ready became the legal foundation for the modern tax system.

With the 16th Amendment in place, Congress passed the first permanent income tax law later that same year. The Bureau of Internal Revenue, which had continued to exist even without an income tax to collect, suddenly had a major new role. The agency began building the infrastructure to assess and collect income tax from millions of Americans. This expansion happened gradually at first—in 1913, only about 3 percent of the population paid income tax—but the agency's size and complexity grew steadily over the following decades.

The agency became the IRS in 1953

For 91 years, the tax collection agency was called the Bureau of Internal Revenue. In 1953, it was reorganized and renamed the Internal Revenue Service. The new name reflected the agency's broader mission: not just collecting taxes, but also enforcing tax law and helping taxpayers understand their obligations. The reorganization also created regional offices and a more centralized structure to handle the growing volume of tax returns.

The 1953 reorganization happened during a period of major growth. After World War II, the income tax had expanded to cover a much larger share of the population. By the 1950s, millions of Americans filed tax returns each year. The IRS had to hire thousands of employees, build processing centers, and develop new systems to handle the workload. Many of the regional IRS offices that exist today were established during this period.

How the IRS changed after World War II

During World War II, the income tax became a mass tax for the first time. To fund the war, Congress lowered tax rates and expanded the tax base so that middle-income workers paid federal income tax. Withholding—where employers deduct taxes from paychecks—was introduced in 1943 to make collection easier. After the war ended, Congress kept both the broader tax base and the withholding system in place.

This shift transformed the IRS from a small agency that dealt with wealthy individuals and large businesses into a mass-collection operation. The number of tax returns filed jumped from about 4 million in 1939 to over 40 million by 1950. The IRS had to hire thousands of new employees, open new offices, and develop new processing methods. The agency also began publishing tax forms and instructions for the general public, a role it had never played before.

The IRS moved to computerized processing in the 1960s

By the 1960s, the volume of tax returns had grown so large that manual processing became impossible. The IRS began using computers to sort, organize, and process tax returns. This was a major technological shift for a government agency. The first computer systems were large, expensive machines that filled entire rooms, but they allowed the IRS to process millions of returns in a fraction of the time manual methods required.

Computerization also allowed the IRS to cross-check information more easily. Employers reported wages to the IRS, and the agency could now match those reports against the income figures on individual tax returns. This made it harder for people to underreport income. Over time, computerization became the foundation for the modern tax system, where most returns are filed electronically and processed by automated systems.

The IRS today operates as a federal agency under the Treasury Department

The IRS is now a bureau of the Department of the Treasury, which handles all federal financial matters. The agency has about 75,000 employees and operates regional offices in every state. It collects income tax from individuals and businesses, enforces tax law, and processes millions of tax returns each year. The IRS also administers tax credits and other programs that Congress has assigned to it, such as the Earned Income Tax Credit.

The modern IRS looks very different from the small wartime office created in 1862, but its basic mission remains the same: to collect the taxes that Congress has authorized and to enforce the tax laws that Congress has written. The agency has adapted to new technologies, changing laws, and growing complexity, but the fundamental structure—a federal agency that assesses and collects income tax—has remained in place since the 16th Amendment made income tax permanent in 1913.

Frequently Asked Questions

Why did the IRS start as a temporary agency during the Civil War?

The federal government needed money to fund the war effort and had no existing income tax system. Congress created the Office of Internal Revenue in 1862 as a quick way to collect taxes on wages and profits. The agency was meant to be temporary, but it became permanent after the war ended because Congress kept the income tax in place.

What happened to the income tax between 1872 and 1913?

Congress repealed the income tax in 1872 after the Civil War ended. It was reinstated in 1894 to raise revenue, but the Supreme Court ruled in 1895 that the federal government did not have the power to collect income tax without amending the Constitution. The 16th Amendment, ratified in 1913, fixed this problem and made income tax permanent.

Why did the agency change its name from Bureau of Internal Revenue to IRS?

The name changed in 1953 as part of a major reorganization. The new name, Internal Revenue Service, reflected the agency's broader role beyond just collecting taxes. The reorganization also created regional offices and updated the agency's structure to handle the millions of tax returns filed each year.

When did most Americans start paying federal income tax?

Income tax was a tax on the wealthy for most of its history. During World War II, Congress lowered tax rates and expanded the tax base so that middle-income workers paid federal income tax. After the war, Congress kept this broader system in place, making income tax a mass tax for the first time.