The first major entrance for Yellowstone was at the north boundary. Before 1903, trains would bring visitors to Cinnabar, Montana, which was a few miles northwest of Gardiner, Montana, and people would climb onto horse-drawn coaches there to enter the park.

In 1903, the railway finally came to Gardiner, and people entered through an enormous stone archway. Robert Reamer, a famous architect in Yellowstone, designed the immense stone arch for coaches to travel through on their way into the park.

At the time of the arch's construction, President Theodore Roosevelt was visiting the park. He consequently placed the cornerstone for the arch, which then took his name. The cornerstone Roosevelt laid covered a time capsule containing a Bible, picture of President Roosevelt, and local newspapers. The top of the Roosevelt Arch is inscribed with "For the benefit and enjoyment of the people," which is from the National Park Service Organic Act of 1916.

Information provided by the National Park Service.