If you are travelling large distances within the US, you’ll be best served by domestic air carriers. Low-cost airlines have made this relatively inexpensive and convenient. The long-distance bus service, Greyhound, is also very inexpensive, but travel time will take you sufficiently longer. Celebrated by travelers the world over Greyhound buses can take you to any of 3700 locations throughout the US. Greyhound offer an impressive range of different fare and discount options including discounts for children, students, the elderly and military personnel. Interstate train service is provided by Amtrak, although due to the geographic size of the country, it is mainly used in the heavily populated north-eastern states, where distances are substantially less. The National rail pass gives you freedom to roam Amtrak’s entire network for around $285. Other passes give you 15 or 30 days in regions such as the East or the Far west from as little as $175. Car rentals are another popular option, especially for travel to neighboring states.