Some folks dread this day ! Income tax was first collected in The Untied States in 1862 to fund the Civil War. It was deemed unconstitutional due to not being apportioned with conformity across the states. The United States once again enacted income tax with the 16th Amendment in 1913. At that time, the filing deadline was March 1. In 1918 the deadline was changed to March 15 and then in 1955 for the most recent change, the filing deadline was moved to April 15th. The day has come to be known as Tax Day.