Today In Wyoming's History: December 6:
1916 Wyoming v. Colorado, dealing with apportionment of water from the Laramie River, argued in front of the United States Supreme Court. It would be re argued twice and decided in 1922.
As this was an original action in front of the Supreme Court, i.e., a trial, it was presented over three days, concluding on the 8th.
The opinion would be issued after rehearing, in 1922.