There are several ways to access Yellowstone National Park, depending on the season and your mode of transportation.
The park is accessible by car during the summer months, with the main entrance roads open from April to November. The most common way to enter the park by car is through the North Entrance near Gardiner, Montana, the Northeast Entrance near Cooke City, Montana, the East Entrance near Cody, Wyoming, the South Entrance near Grand Teton National Park and Jackson, Wyoming, and the West Entrance near West Yellowstone, Montana. Some roads, like the road between the North Entrance and the Northeast Entrance, are closed during the winter.
By Snowmobile or Snowcoach
During the winter, when most park roads are closed to vehicles, visitors can access the park by snowmobile or snowcoach. These guided tours depart from locations outside the park and provide transportation to various destinations within the park.
By Shuttle Bus
During the summer, the park operates a shuttle bus service that runs between popular destinations in the park. This service is intended to reduce traffic congestion and parking issues and is a great way to visit popular destinations such as Old Faithful and the Grand Canyon of the Yellowstone.
The closest major airports to Yellowstone are Bozeman and Cody, both of which are located about an hour's drive from the park. Visitors can also fly into Jackson Hole Airport, which is about 2 hours drive from the South entrance of the Park.
It's worth noting that the park is quite big and remote, so it's best to plan ahead, regardless of your chosen method of transportation and have a detailed plan on how to move around and what to expect once inside.