Legal - General Holidays (State)

Holiday   Definition  2015  2016
 New Year's Day January 1     Friday January 1
 Martin Luther King Jr. Day 3rd Monday in January     Monday January 18
 Lincoln/Washington Birthday  3rd Monday in February    Monday February 15
 Memorial Day  Last Monday in May  Monday May 25  Monday May 30
 Independence Day  July 4  Saturday July 4   Monday July 4
 Labor Day  1 st Monday in September  Monday September 7  Monday September 5
 Columbus Day  2 nd Monday in October  Monday October 12  Monday October 10
 Election Day      Tuesday November 8
 Veteran's Day  4th Thursday in November  Wednesday November 11  Friday November 11
 Thanksgiving Day  4th Thursday in November  Thursday November 26  Thursday November 24
 Christmas Day  December 25  Friday December 25  Sunday December 25
 Other important days      
 Mothers Day  Second Sunday of May  May 10  May 8
 Fathers Day  Third Sunday of June  June 21  June 19

So Montana does not have their own groundhog day from what I can tell.  However a few years back we visited Ulm Pishkun where there are tons of prairie dogs.  I still think it would be nice to consult with them.