1926 - Queen Marie of Rumania

Queen Marie traveled through Wyoming by rail car during a lengthy vacation tour of the United States. Her only stop in Wyoming was a brief visit to Casper on her way from Glacier National Park to Denver. She admired the tidy bungalow houses and toured the Standard Oil Company oil wells.

1984 - Queen Elizabeth II of England

Queen Elizabeth visited northern Wyoming, staying at the Wallop family ranch near Sheridan and visited the Bradford-Brinton Museum.

http://www.nytimes.com/1984/10/13/us/ranch-s-royal-guest-arrives-for-weekend.html