The R&R Market on Main Street in San Luis, Colorado, has been open since 1857. The current building, seen here, has stood since the late 1940s.

(Nathaniel Minor/CPR News)

The latest rundown of the five most imperiled historic buildings and sites in Colorado stretches across southern Colorado. 

Colorado Preservation identifies the locations every year to raise awareness as the organization begins levying its resources to preserve the sites.

Weather in the mountains, development pressures along the Front Range and abandonment in rural areas can all threaten historic buildings, said Kim Grant, the Endangered Places program director for Colorado Preservation, Inc.

In 22 years, the organization has identified 125 historic sites. Colorado Preservation, Inc. has saved 47 and is in the progress of aiding 44 more while 25 remain on alert. Only seven sites have been lost.

These are Colorado Preservation, Inc.'s five most endangered places.

The R&R Market in 1960.

(Courtesy Denver Public Library, Rocky Mtn. News Archives, Romero Family photo)

R&R Market

The general store in the San Luis Valley is the state's oldest continually operating business. Felix and Claudia Romero, the R&R Market's aging owners, are ready to retire, but there are no successors in line.

"I hate to be the one to break tradition. I really do,” Felix Romero told CPR News in 2017. “But I can't spend the rest of my life here either. We're now at that age where I've got to make some hard decisions. And I'm going to make them."

If the R&R Market was lost, the historic two-story adobe building wouldn't be the only thing missed. Its closing would seriously impact the community's economy.

Potatoes were once a major cash crop in the San Luis Valley. The cellars left behind from the tuber's business boom are on Colorado Preservation, Inc.'s list of endangered places.

Courtesy of Colorado Preservation, Inc.

San Luis Valley Potato Cellars

Idaho isn't the only state with a claim to potato farming.

Colorado's San Luis Valley has long been a major tuber cultivator, and scores of potato cellars dot the landscape. The buildings were built between the late 1800s and early 1900s and are cool, dark and naturally climate-controlled to store potatoes. They mostly fell out of use in the 1960s.

But over the years the cellars have begun to deteriorate, and because many are on private lands, their futures are uncertain. Preservation Colorado hopes to survey the remaining sites to identify the ones most worth saving, Grant said.

The ruins of the McIntire Ranch and Mansion outside of Florence, once the home of Gov. Albert McIntire.

Courtesy of Colorado Preservation, Inc.

McIntire Ranch and Mansion

The third San Luis Valley entry on Colorado Preservation's list was once the home of Gov. Albert McIntire, who served from 1895 to 1897.

The adobe building was constructed around 1880 in Conejos County. McIntire's work as governor kept him away from the ranch, eventually leading to his divorce from his wife Florence, who won the rights to the home and continued to live there.

A horse-drawn fire wagon leaves the Hose Company No. 3 Fire Museum in Pueblo.

Courtesy of Colorado Preservation, Inc.

Hose Company No. 3 Fire Museum 

This Pueblo firehouse was the third in the country to unionize after companies in Pittsburgh and New Orleans.

The firehouse was constructed in 1895 and oversaw the transition from horse-drawn fire wagons to fire engines. It was operational until the 1970s, when it became a museum.

Today, the building is in decline and the volunteers who run the museum don't have the resources on their own to maintain it.

The sign above the Iglesia De San Antonio-Tiffany Catholic Church in La Plata County.

Courtesy of Colorado Preservation, Inc.

Iglesia De San Antonio-Tiffany Catholic Church

This small church outside Durango is one of the last markers of Hispano history and culture in La Plata County near the New Mexico border. 

Iglesia De San Antonio Church was built in 1928 in Tiffany, a small town along the Denver & Rio Grande Railroad to Durango. Today it's the only standing building from the settlement.

Editor's Note: This story has been updated to reflect the history of potato farming in the San Luis Valley and the location of the McIntire Ranch.