The government came for the horses at dawn. It was spring 2003 and it was foaling season. A helicopter flew low over Pine Valley, herding them to corrals. Some prematurely gave birth, others were trampled. Armed federal agents stood by. By the end of the day, over 500 horses were taken to be auctioned off to a local rancher. Not long afterwards some 50 carcasses were dumped – the horses had starved to death.

Carrie Dann, a diminutive Western Shoshone grandmother who owned the horses, refuses to talk about it. “Indians love horses,” is all she’ll say. But she thinks it caused the death of her sister, Mary, who died last April. “After that,” she says, “Mary went down real fast.”

The 2003 round-up was the fourth military-style operation in one of the longest-running land disputes in the history of America. For over 30 years, Carrie and Mary Dann have fought the US government for Western Shoshone rights to 60m acres of land that stretch through Nevada into neighbouring states. Until now, the harassment has hardly scratched the conscience of America, but that might be about to change.

In March, in an unprecedented document, the UN demanded that the US government halt all actions against the Shoshone and find a solution acceptable to them and in accordance with their rights. This landmark decision could force the government to transform antiquated federal Indian law. And if it does it will be in no small part down to the Dann sisters.

What she lacks in physical stature – she barely scrapes 5ft – Carrie Dann makes up for in presence and sheer bloody-mindedness. Her face is weathered by decades in the saddle and a 20-a-day habit – and her swearing doesn’t endear her to government officials. “The Indian wars ain’t over yet,” she says fiercely. “They’re still happening here and now.” But, despite her defiance, she admits she’s still afraid the US government will confiscate her ranch to pay outstanding fines for disputed grazing fees.

The Dann ranch isn’t much to look at. A single-story rambling clapboard house, it’s surrounded by tall cottonwood trees and rusting wrecks. Uncle Clifford, who famously threatened to douse himself in gasoline when the “feds” first confiscated the family livestock in the early 1990s, earning nine months in state prison as a result, lives in a trailer in the garden. He’s now profoundly deaf. Carrie’s severely disabled son is playing in the cabin of a tractor in the front yard.

Panes of glass have been replaced by cardboard and there’s no central heating. Cooking is done on a wood-burning stove. The only things that place the ranch in the 21st century are the solar panels that replaced the generator last year.

But Carrie doesn’t care about home comforts. Her grandmother, she tells me proudly, never had a bed. Anyway, the land is all that matters. “We’ve been here since time immemorial,” she says, as we make our way to a small dam to catch brown trout for dinner. “I was born here and this is where I’ll die, whatever the government says.”

The ranch is dwarfed by the Nevada landscape. Crescent Valley stretches away from it for miles like a vast carpet of desert shrubs and wild flowers.

To the naked eye, it’s a vast plain of nothing much – but the ranch is on some of the most expensive real estate in the world. Carrie Dann is, quite literally, sitting on a gold mine.

Just down the road, the Carlin Trend, discovered in the 1960s, is the second largest gold depository in the world after Witwatersrand in South Africa, but the entire state is covered with open pits. Mining has always been Nevada’s raison d’etre. There was a lull at the beginning of the 20th century; silver ran out and gold was yet to be discovered so the state legalised divorce, gambling and prostitution. But today nearly 10% of the world’s production of gold ­– over half of US production – comes from Nevada.

Carrie’s ranch sits on the slopes of the Cortez mountain range, first prospected in the original gold rush but as yet untapped. Not long before the 2003 round-up, Cortez Mining (a joint venture between Placer Dome, the largest mining operation in the area, and Rio Tinto) tried to introduce legislation to privatise 60,000 acres for mining around Mount Tenabo, the most imposing mountain in the range.
Tenabo is sacred to the Shoshone for reasons other than gold, and the ensuing uproar killed the bill but, for the Danns, this was just another battle in an ongoing war of attrition.

The Danns’ legal dispute began in 1973 when the Bureau of Land Management fined the sisters for grazing their livestock on “public lands”: that is, land owned by the federal government. The sisters never had any intention to pay. As far as they were concerned, they were grazing ancestral land ratified in the Treaty of Ruby Valley in 1863. Collection notices still arrive at the tiny local post office but Carrie doesn’t even bother to open them. “I probably owe $5m by now,” she laughs hoarsely.