The Revenue Act of 1861 is enacted, levying the first income tax in the United States.
Rates under the Act were 3% on income above $800 (adjusted for inflation: $18,875 in as of 2009 dollars ) and 5% on income of individuals living outside the country.
The income tax provision (Sections 49, 50 and 51) was repealed by the Revenue Act of 1862. (See Sec.89, which replaced the flat rate with a progressive scale of 3% on annual incomes beyond $600 ($12,742 in 2009 dollars) and 5% on incomes above $10,000 ($212,369 in 2009 dollars) or those living outside the U.S., and perhaps more significantly it was explicitly temporary, specifying termination of income tax in "the year eighteen hundred and sixty-six").
This tax was later completely repealed, but re-enacted during World War I. The burden on taxpayers has been increasing almost continuously ever since.