Quote Originally Posted by Pour1Malt
April 6 -- Celebration of Tartan Day approved by the US Senate, in recognition of the monumental achievements and invaluable contributions made by Scottish Americans. (1998)
Canada has been celebrating "National Tartan Day" since 1993. The idea and motivation for creating a similar American holiday was provided by the Scottish Coalition, a group of national Scottish- American cultural organizations.

http://www.tartanday.org/history.htm
http://www.electricscotland.com/tartnday.htm

Let's not forget Samhain in October (now mostly known as Halloween) http://www.celticspirit.org/samhain.htm

July 22nd Stornoway born Alexander MacKenzie made it across Canada, becoming the first white person north of Mexico to reach the Pacific by crossing overland. Almost a decade before Lewis and Clark.
http://www.collectionscanada.ca/2/6/h6-221-e.html
http://www.amvr.org/
http://en.wikipedia.org/wiki/Lewis_and_Clark