Judge John W. Meldrum, the “Grand Old Man of Yellowstone”, became the first United States Commissioner in Yellowstone National Park from 1894 to 1935. He was born on September 17, 1843 in Caledonia, New York. He was closely associated with the Republican Party and was a delegate to the 1884 National Republican Convention. President Chester Arthur, impressed with his participation in the convention, appointed him to be Surveyor General of Wyoming Territory. He left this office at the end of 1885. In 1891, he was appointed by Governor Warren to be the Circuit Court Clerk of the State of Wyoming, essentially fulfilling the role of Secretary of State. When Governor Warren was elected as a Senator for the territory, Meldrum was appointed acting governor of the territory, and served as acting governor of the state of Wyoming for a few days when it was admitted into the Union.

After the passing of the Lacey Act of 1894, which created the office of United States Commissioner to judge crimes committed in National Parks, Meldrum filled the office in Yellowstone. His primary purpose was to hear trials for crimes committed within the park and assign fines or order the transfer of cases to federal court. He served as the United States Commissioner for over forty years until he retired in 1935, and he died a few months later.