Tartan Day was established in 1991 in Canada in response to action initiated by the Clans & Scottish Societies of Canada, and in America on March 20th 1998, by US Senate Republican majority leader Trent Lott (Senate Resolution 155)

...Whereas this resolution recognizes the monumental achievements and invaluable contributions made by Scottish Americans that have led to America's preeminence in the fields of science, technology, medicine, government, politics, economics, architecture, literature, media, and visual and performing arts; ...Whereas these numerous individuals, clans, societies, clubs, and fraternal organizations do not let the great contributions of the Scottish people go unnoticed: Now, therefore, be it Resolved, That the Senate designates April 6 of each year as "National Tartan Day". (3)