There are approximately 640 million acres of public land in the United States but roughly 16 million acres of that land is ‘landlocked’ by private owners, making the land inaccessible.

Knowing how to access these public lands is another challenge.

This notion poses a hurdle and problem for Jackson, Wyoming professional skier Griffin Post, who decided to make a film about the issue, and titled his film “Inaccessible.”

“I reached a point in my career where I wanted to have a bit more impact in my community,” Griffin said. “One of the impetus’s for this project was my awareness about public lands and access issues that was really born in hunting and fishing.”

The film, which premieres on Tuesday in Boulder at the Boulder Theatre, shares a skier’s perspective on how to approach accessing public lands.

Living at an early age in urban Chicago, Post had not really experienced public land until he relocated to the West.

But once in Idaho, a state rich with outdoor users as well as public land, Post began to understand why public land was important for all.

While skiing with his mother, Post asked her, “Mom, whose land is this?” and she responded back, “This is everybody’s.”

Taking that notion to heart, Post began adventuring more in the outdoor world, eventually making his way into ski films in the 2010s with Teton Gravity Research.

A decade later, Post said, he was speaking on an outdoor recreation panel when a hunter spoke up about the $1.5 billion raised annually through licenses, fees, tags, taxes and cleanup efforts the hunting industry collects.

Post then asked himself, “How powerful would it be if skiers and snowboarders showed up in the same way to protect public lands?”

Post recruited fellow backcountry rider Emilé Zynobia (a climate specialist) and Eric Jackson (an avid hunter and angler) to work on “Inaccessible” with him in the Crazy Mountains of Montana.

Before the trio entered the wilderness, however, Post needed beta on the terrain. With help from onX Maps to sort through data where the three could access public land for good ski terrain while avoiding private land, Post found hope.

“I went through this spreadsheet of literally hundreds and hundreds of points in every state, like every point above 5,000 feet, or something that was inaccessible,” Post said.

Post went through the spreadsheet, looked at the ski terrain, and ultimately landed on accessing the Crazy Mountains of Montana, aka the Crazies.

“They (the Crazies) have this checkerboard pattern of public land that’s overlaid on these pretty incredible ski objectives,” Post.

But other challenges were also encountered.

Post had to piece together where he, Zynobia and Jackson could make base camp for their ski outing, and as Post said in the movie, “Our day will be dictated by imaginary lines.”

The film also features interviews with Jessi Johnson with the Wyoming Wildlife Federation, Shane Doyle, an educator and advocate of public lands from the Apsaalooke Nation, and Joel Webster, chief conservation officer at the Theodore Roosevelt Conservation Partnership.

“When land is locked up, it automatically looses its cultural and spiritual value because it doesn’t belong to you anymore,” Doyle said. “You talk to people who go to the Crazy Mountains. There’s no place like them.”

The Crazies’ tallest peak, Crazy Peak at 11,214 feet, is on private land.

“In Montana, the penalty for trespassing is six months in prison,” Zynobia said in the film. “But land owners have been known to sue trespassers for millions of dollars. Crossing a private boundary is a risk we are not willing to take.”

The film captures a three-day adventure arc, following a scouting and set-up-camp-day on day one, a first attempt at ascension and descension of a couloir on day two, and facing a risky, corner crossing between two private land squares from one public square to another on day three.

The idea of corner crossing is a user ‘steps over’ private land to access the public land on the other side.

“In Wyoming, a group of four hunters decided to cross some corners to access public land to hunt elk,” Webster said in the movie.

“The land owner called the sheriff’s office and had a civil trespass lawsuit brought against them,” Johnson said.

“Inaccessible” will be at the Boulder Theatre on Tuesday night with doors opening at 5:30 p.m. Tickets are available. General admission tickets are $10.

The film will be available to stream starting Wednesday.

“Go camping, backpacking, snowboarding, fishing, hunting, whatever,” Jackson said near the end of the film. “Having that freedom is, do not mistake, is a privilege. I think it is pretty simple. Protect what you love and if you love public land, then fight for it.”