KEBLER PASS —There’s a new town in Colorado. It has about 50 buildings, including a saloon, a church, a jail, a firehouse, a livery and a train station. Soon, it will have a mansion on a hill so the town’s founder can look down on his creation.

But don’t expect to move here — or even to visit.

This town is billionaire Bill Koch’s fascination with the Old West rendered in bricks and mortar. It sits on a 420-acre meadow on his Bear Ranch below the Raggeds Wilderness Area in Gunnison County. It’s an unpopulated, faux Western town that might boggle the mind of anyone who ever had a playhouse. Its full-size buildings come with polished brass and carved-mahogany details and are fronted with board sidewalks and underpinned by a water-treatment system. A locked gate with guards screens who comes and goes.

Koch’s project manager has told county officials that the enclave in the middle of the 6,400-acre Bear Ranch won’t ever be open to the public. It is simply for Koch’s amusement and for that of his family and friends — and historians. It is the ultimate repository for his huge collection of Western memorabilia.

“It’s the kind of stuff I guess you would expect a billionaire to construct. It’s like something out of a ‘Gunsmoke’ movie set,” said Ramon Reed, chairman of the Gunnison County Planning Commission.

The commission recently OK’d a 22,000-square-foot residence for Koch above the town that already has two buildings in excess of 11,000 square feet.

Koch, known as “Wild Bill” to some of his friends, is the founder and president of the energy company Oxbow Group, which operates the Elk Creek Mine near Somerset. Forbes estimates Koch’s net worth at close to $4 billion.

Bill Koch is the brother of David and Charles Koch, two other billionaires who have made headlines in recent years for shoveling money to conservative causes, including the Tea Party movement.

But Bill Koch has mostly made waves for collecting rare wine, winning the America’s Cup sailing race and, most recently, buying up every bit of valuable Western memorabilia that comes up for sale.

He paid $2.3 million for a photograph of Billy the Kid at an auction last year. He bought out the Buckskin Joe Western town near Cañon City for $3.1 million in 2010. He owns Jesse James’ gun, Wyatt Earp’s vest, Sitting Bull’s rifle and a flag that belonged to Gen. George Custer.

He has more Charles Russell paintings and Frederic Remington bronzes than most museums.

In fact, he has crammed part of a museum with his collections this year. His Western art and artifacts were on display at the Society of the Four Arts at the Palm Beach Museum in Palm Beach, Fla. Palm Beach is where Oxbow is based.

In an interview this past spring with arts blog the Fine Art Notebook, Koch noted that he would be moving the collection to the Centennial State and told the interviewer, “I shouldn’t tell you this, but I am building my own Western town in Colorado.”

He also revealed that his wife told him he should go on the television show “Hoarders.” It’s a show about people obsessed with amassing things.

Koch will have a lot of room to keep his collections in Colorado. Around 50 buildings, along with a water-treatment system, have been permitted by Gunnison County in the past two years. Recently, the mansion — a home that will be the largest in Gunnison County — made it through the planning process.

Reed said Gunnison County has no restrictions on the size of residences, but the Koch home came before the planning commission because of a regulation that a residence of that size must not be “obtrusive.”

Reed said they took into account that a third of the Koch mansion will be underground and it will be blocked by a hillside. Koch’s designer and project manager agreed to tone down lighting so it won’t be shining into the Raggeds Wilderness.

Koch also agreed to downsize a bit. The home is expected to come in at closer to 21,000 square feet in the final plans when one wing is removed.

Koch, who was not available for comment, also owns four properties in upper Castle Creek Valley near Aspen, including the 17,000-square-foot Elk Mountain Lodge that he turned into a personal residence when he bought it and the other three properties for $51 million in 2007. Elk Mountain was formerly a high-end hunting lodge.

That residence is along a county road, so it doesn’t have the privacy of Bear Ranch.

Koch is trying to sew up more privacy at Bear Ranch through a land swap that brought his name into the public eye in Delta and Gunnison counties.

The controversial swap would give the government properties near Blue Mesa and in Dinosaur National Park in exchange for a public swath that cuts through his ranch.

Nancy Lofholm: 970-256-1957, nlofholm@denverpost.com or twitter.com/nlofholm