A new feature has appeared at smoke shops in Montana, gas stations in the Carolinas and delis in far-flung corners of New York City: a brightly-lit bitcoin ATM, where customers can buy or sell digital currency, and sometimes extract hard cash.

The machines have multiplied quickly through the United States over the past year, fueled by a frenzy in crypto trading that sent bitcoin prices over $58,000.

Kiosk operators such as CoinFlip and Coin Cloud have installed thousands of ATMs, scouring areas competitors have not yet reached, executives told Reuters.

“I just assumed there was demand and people wanted bitcoin everywhere,” said Quad Coin founder Mark Shoiket, who flew to Montana after scanning a U.S. map for bitcoin ATM deserts.

During a week-long road trip, he found 7 places to install machines, including 406 Glass, a store in Billings, Montana, that sells tobacco, vape juice and colorful glass pipes.

According to howmanybitcoinatms.com, an independent research site, there were 28,185 bitcoin ATMs in the United States as of January. Around 10,000 came within the prior 5 months.

Bitcoin’s growing popularity has been the main driver for new installations.

The reasons people use ATMs rather than transacting online vary. Some get paid in cash, some lack bank accounts, some want to send remittances abroad or want anonymity, while others feel more comfortable interacting with a physical machine.

Rebecca White, a 51-year-old bitcoin investor who lives in the Pittsburgh area, makes larger investments online and uses bitcoin ATMs when her family has extra money.

“When we do our grocery shopping and we have $60 left, I will stop at the bitcoin ATM,” said White, who works in the nuclear power industry.

Some machines only offer bitcoin, while others let customers invest in various digital currencies. Few bitcoin ATMs can actually spit out cash, and they cost more than regular ATMs or transacting online.

Pamela Clegg, director of financial investigations and education at cryptocurrency compliance firm CipherTrace, said fees range from 6% to 20% of a total transaction. Fees vary depending on the location and Bitcoin ATM operator.

“The growth of the ATM market – it is not even a gentle increase, it is almost a 45% increase,” said Clegg. “The growth is quite astonishing.”

Government agencies have raised red flags about some machines because of their cost and the potential for illicit activity. The New Jersey State Commission of Investigation detailed some of those concerns in a February report titled “Scams, Suspicious Transactions and Questionable Practices at Cryptocurrency Kiosks.”

None of those concerns have stopped the industry’s growth.