December  20

1803 In April 1803, the United States purchased the 820,000 square miles of what had been French Louisiana from France for $15 million. On November 30, 1803, Spain, which had never given up the area, officially transferred it to France. In a second ceremony on December 20, 1803, the French turned Louisiana over to the United States. What would become a great part of Wyoming was included in this purchase.

1889 On December 20, 1889, the name and location of the La Belle Post Office was changed to Moorcroft.