If you’ve been outside in the last decade, you’ve likely noticed that wool—one of the world’s oldest performance fibers—is having a bit of a moment right now.

Long the material of choice for outdoorsman (Sir Edmund Hillary and Tenzing Norgay both wore wool when they sumitted Mount Everest in 1953) because of its warmth, it had the unfortunate reputation for being itchy and delicate, and it fell out of favor in 1979 when Malden Mills developed the first synthetic base-layer material. It wasn’t until the launch of Icebreaker and Smartwool—two brands that popularized the use of the much-softer merino wool—in 1994, that the natural fiber regained its foothold in the outdoor market.

Problem is, most of that merino comes from overseas (primarily from New Zealand and Australia), and the factories to process it tend to be in China. But over the last year, a few small U.S. companies have made big strides in bringing the entire wool industry back to American soil.

"The other wool brands on the market were missing soul," says Robert “Bernie” Bernthal, founder of Duckworth, a Montana-based wool company that’s leading the charge for American-sourced wool. "Wool is sustainable, sure. But if people knew how far their wool traveled, especially in the outdoor world, they’d be surprised. Wool grown in New Zealand has to be sent 5,000 miles to China to be processed.”

Bernthal had a different vision for Duckworth. He wanted every stage of the process, from raising the sheep to processing the wool to sewing the apparel, to take place in the U.S.

There's a reason great wool comes from the Rockies: Cold winters, hot summers, lots of sunshine, and the right vegetation.

Five years ago that would’ve been almost impossible: crucial stages in wool processing were moved overseas decades ago. But in 2011, thanks to the strengthening of the Berry Amendment, which required military goods to be sourced domestically, the American Sheep Industry spent $800,000 to bring superwash machinery—a treatment that prevents wool from shrinking—to South Carolina.

The new technology was a game changer for the U.S. wool industry, as it filled a crucial gap in the processing supply chain. "The Berry Amendment was an enormous impetus for us to buy the equipment,” says Rita Samuelson, marketing director at the American Wool Council. “The amendment says that textile products have to be all-American, from the wool to the buttons. You used to be able to send wool overseas for processing, but the amendment has gotten stricter, so that's no longer the case."

The other big breakthrough for American-sourced wool came from advances in genetics. Bernthal and co-founder Graham Stewart partnered with rancher John Helle, an expert in sheep genetics, when they started Duckworth. The company, now a little over a year old, has a small staff in Bozeman and some 12,000 sheep that graze on the 25,000-acre Helle Ranch outside of Dillon, Montana.

Helle knew the Rockies could produce great wool: cold winters, hot summers, lots of sunshine, and the right vegetation are the perfect Petri dish to breed sheep covered in high-quality, soft fibers. “Through years of natural selection, we developed a strain of rambouillet that were well adapted to the harsh climate of Southwestern Montana,” says Helle, whose flock yields wool with micron counts (a measure of how fine the wool is) that average below 20 and as fine as 15. For reference, a carpet will have micron counts around 25, while cashmere’s are 14. “Over the past 30 years, quantitative genetic selection through the aid of computers has improved our sheep even more. We can improve traits such as finer, softer wool, or ewes that have more lambs at birth."

The economics help make all this R&D viable: studies have shown American consumers will pay a premium for products that are made in the U.S. According to a study done by Consumers Reports, 77 percent of Americans are willing to pay more for a product that’s made in America.

The same study also found that labels don’t tell the whole truth about how much of the product is made in the U.S. You can be certain, however, that everything produced by U.S. wool companies, like Duckworth, is 100-percent American made.