Why, you might ask? Just for the heck of it!
The Aussies say it's a unique way to see the country. They left Baltimore on June 27 and have been taking in the sights of the U.S.A. ever since.
Today they rolled down Pacific Coast Highway in Huntington Beach on the last leg of their trip.
"It's been a great challenge and a great adventure to boot," says Neville Thompson, a cross-country tractor driver.
"Never been out of Australia, personally, it's been bloody great," he says.
Neville and his group also issued a challenge to Americans. They'd like us to bring our tractors "down under" and do a similar cross-country trek across Australia.