Bert P. Mill was a local photographer who resided in the Idaho Falls area of eastern Idaho. He was active during the 1880s and 90s. His studios were listed in both Idaho Falls and Correctionville, Idaho. He views are quite scarce but generally show interesting subject matter, including scenes of people fishing, the sheep and wool industry and various locales in and around Idaho Falls.

His only known Yellowstone view is shown below. It is untitled, but clearly shows a woman on a horse along the rim of the Grand Canyon of the Yellowstone.

Untitled view of a woman on horseback at the Grand Canyon of the Yellowstone.