September 25

1869 The Cook-Folsom-Peterson Expedition continued its exploration of what would become Yellowstone National Park. On September 26, they traveled along the shoreline of Yellowstone Lake to the West Thumb Geyser Basin. They spent the next two days exploring the area.

1909 The people of Upton voted for incorporation of the town.

1912 The USS Wyoming (Battleship #32) was commissioned at the Philadelphia Navy Yard.

1997 Lake Guernsey State Park was designated a National Historic Landmark.