WATCH: When Robert Redford Rode Wyoming’s Outlaw Trail

From Canada to Mexico, a secret trail once helped the outlaws of the old West travel, mostly unseen, with folks helping them along the way.

Today, the term "Wyoming Outlaw Trail" can refer to a historic 205-mile scenic drive in Carbon County, a system of mountain biking/hiking trails near Cody, or a specific hiking trail at Outlaw Cave near Kaycee.

Back in 1975, actor Robert Redford helped produce a short documentary on the trail. Much of what is in the video takes place in Wyoming, near the once hidden but now famous Hole in the Wall and Outlaw Cave.

In a National Geographic documentary, actor Robert Redford discusses the Outlaw Trail. The historic route runs from Montana to Mexico and was used as an escape route by Wild West outlaws like Butch Cassidy.

Redford traveled the trail in 1976, riding horseback, by car, and boat, and visited locations in states like Wyoming, Utah, and Montana, where he met locals and explored the landscapes that shaped the lives of outlaws. An accompanying book of the same name was also published.

The trail came down through Kaycee to the Hole In The Wall, but then turned west over to South Pass City and Atlantic City. From there, it was south to Browns Park

Several books and maps show where sections of the Outlaw Trail were and what can be explored today. There is even camping in some of those areas that allows a person to see what The Wild Bunch saw back then.

Outlaws such as Butch Cassidy, the Sundance Kid, and the James brothers. Following existing Western routes such as the Oregon Trail, the highway connected towns and natural hideouts essential for bandits escaping the law.

Some in Western communities were sympathetic toward the outlaws. Many, like Cassidy, were seen as Robin Hoods, fighting for common people who were under siege by economic forces, corporate encroachment, and other changes occurring in the Old West.

The book Wyoming's Outlaw Trail details the history, folklore, and geography behind some of Wyoming's outlaw towns and hideouts—chief among them the Hole in the Wall and Red Desert.

Also highlighted are the deeds of the robbers, lawmen, and ordinary folk who rode those dusty trails during the late 1800s and early 1900s.