For months now, the population has dwindled at the Oceti Sakowin camp, the hub of the movement to stop the Dakota Access oil pipeline. At its peak last year, the 80-acre swath of prairie was home to 10,000 or more Native Americans and environmental activists who transformed the federally-owned land in North Dakota into a sort of communal village, complete with shelters, mess halls and community centres.
But the harsh Midwestern winter and a series of legal defeats in the fight over the pipeline took a toll on the activists' numbers. By mid-February, only a couple hundred stalwarts remained.
By the end of the day Wednesday, the last of them are expected to clear out, as well - either voluntarily or by force. One of the largest demonstrations of its kind will come to an end.
A mandatory evacuation order from the North Dakota governor and the US Army Corps of Engineers is set to take effect at 2pm local time (9am NZT). Anyone who stays behind will face arrest and trespassing charges.
Activists say they're bracing for the worst. Tribal leaders and camp organisers have urged anyone who decides to defy the evacuation order to remain "peaceful and prayerful." But some worry that Wednesday could bring a repeat of the mass arrests and violent clashes that took place between police and protesters in the fall.
"A massive, militarised police force will be moving through camp, going through structures and arresting people," John Bigelow, a member of the Standing Rock Sioux Tribe who has lived at the camp for the past six months, told The Washington Post. "I expect there will be a certain number of people who will be in peaceful prayer who are willing to take a stand both against the pipeline and for indigenous rights. My greatest fear is that something may go awry and some people may get hurt."
Officials say Wednesday's evacuation is necessary for safety reasons. Part of the camp sits on a floodplain, they say, which could create dangerous conditions as the weather warms and the snow melts. Floodwaters could also wash trash and debris from the camp into the nearby rivers, according to North Dakota Attorney General Wayne Stenehjem.
"The threat to the environment is very real and the situation is urgent," Stenehjem said in a statement last week. "This is about protecting the land and the waters of the Missouri River from pollution from tons of garbage, human waste and other hazardous items."
State officials said they have set up a "transition centre" in Bismarck to help activists leaving camp. "The ideal situation is zero arrests," North Dakota Governor Doug Burgum told the Associated Press on Sunday.
Dakota Access opponents argue the 1,172-mile pipeline threatens the main water supply for the Standing Rock tribe by passing under a Missouri River reservoir. They also say it violates long-standing treaties and disrupts sacred lands. Legal challenges from the tribe have failed to stop the project from moving forward, although the Obama administration temporarily halted construction in December. The order was recently reversed by the Trump administration, and drilling commenced in early February.
Activists began camping near the drill site over the summer, setting up the Oceti Sakowin camp and several others along the Cannon Ball River. Armed agents from the National Guard, the Morton County Sheriff's Department and other law enforcement agencies have since surrounded the camps, erecting spotlights and razor wire on the hills nearby and barricading one of the main roads into the area.
From the beginning, the tribe and camp organisers have called on activists to protest peacefully and avoid confrontations with law enforcement. But some demonstrations have given way to violence.
In October, authorities used rubber bullets, pepper spray and high pitched warning tones against protesters who tried to start a new encampment closer to the pipeline. Some activists responded by throwing rocks and other objects at police and torching abandoned cars on the road. More than 100 people were arrested, including a protester who allegedly fired a gun at deputies. Tensions erupted again less than a month later, when police turned water cannons on activists in subfreezing temperatures. In total, Morton County law enforcement officials have arrested more than 700 people since the demonstrations began.
Many of the remaining protesters are expected to leave Wednesday on their own accord. Women, children and elders will stage a symbolic march out of camp around noon, activists say. Buses will arrive early in the day to transport people to Bismarck, where the state government will provide food and lodging for the night, and help people arrange travel home, according to the sheriff's department.
Others have vowed to stay and non violently resist.
"We'll make it difficult for them to handcuff us," Bryce Peppard told the AP, "but there will be no forceful opposition."
Bigelow, of the Standing Rock Sioux, said he too plans to stay past the 2pm deadline, but only as an observer. He set up the Oceti Sakowin camp media when he arrived last year and built the website that organisers have used to share news and solicit donations for the anti-pipeline movement. His goal, he said, is to document the response from authorities and the last moments in camp.
"I believe that my obligation is to remain as long as the Oceti Sakowin camp exists," Bigelow said. "We are there to document it until the end. That is why we're here."
"Some of us," he added, "feel once again we are being forced off of our land in a way that is reminiscent of historic trauma."
Over the past few weeks, activists have started clearing out the camp, though it has not been an easy task. Melted snow has turned the campgrounds into a mud pit, making it difficult for vehicles to drive in and out, as The Post's Joe Heim has reported. On top of that, few people are left to help out. But trucks arrive regularly to haul trash, and the remaining volunteers have busied themselves dismantling structures, collecting debris and moving leftover supplies out of camp.
"It's very sad that we have to leave here," Sean Kasto, a member of the Cheyenne River Sioux, told the Bismarck Tribune on Tuesday. "A lot of us left our daily lives to be here and I tried my hardest to be here every day."
The scene in the camp's final hours Tuesday night was upbeat. Tribe members and activists huddled around campfires until late into the night, singing Lakota prayer songs, beating on hand-drums and shouting "water is life," one of the movement's signature slogans. Some of the festivities were streamed in a Facebook Live video. At one point, one of the performers can be heard joking, "Who's first night is it here? Bad night to come - just kidding, just kidding."
Jen Byers, a photographer from California, was among those who stayed for the last night in camp. She spent three weeks there late last year, working in the camp's media tent, then returned earlier this month. She said activists, concerned about another crackdown by law enforcement, were "hoping for a miracle."
"If there are not people here tomorrow, it will say less about their resilience and so much more about the militarised violence used against them," Byers told The Post. "The planning and dedication in this resistance movement is unshakably, incredibly strong."