The pipeline runs from the Bakken oil fields in western North Dakota to southern Illinois, crossing beneath the Missouri and Mississippi rivers, as well as under part of Lake Oahe near the Standing Rock Indian Reservation.

[12] Voicing concerns for damage to wildlife habitat and sacred sites, the Sac & Fox Tribe of the Mississippi in Iowa (Meskwaki Nation) also objected to the route and formally lodged their opposition in early 2015.

[25][26] On September 20, 2016, Standing Rock Tribal Chairman David Archambault II addressed the UN Human Rights Council in Geneva, Switzerland, where he called "upon all parties to stop the construction of the Dakota Access Pipeline."

"[27] On September 22, 2016, Victoria Tauli-Corpuz, a United Nations expert on the rights of Indigenous peoples, admonished the U.S., saying, "the tribe was denied access to information and excluded from consultations at the planning stage of the project, and environmental assessments failed to disclose the presence and proximity of the Standing Rock Sioux Reservation."

In another such case, LaDonna Brave Bull Allard, who founded Sacred Stone Camp, said that when her daughter was arrested and taken into custody she was "strip-searched in front of multiple male officers, then left for hours in her cell, naked and freezing."

[41] Protesters said they were blasted with high-pitched sound cannons and described being held in cages that "appeared to be" dog kennels, in the garage of the Morton County Correctional Center, with identifying numbers written on their arms by the arresting officers.

[46] [citation needed] The Morton County Sheriff's Department said in a statement: "Protesters' escalated unlawful behavior this weekend by setting up illegal roadblocks, trespassing onto private property and establishing an encampment, has forced law enforcement to respond at this time.

[58][59] The Standing Rock Medic & Healer Council refuted law enforcement's claims in a statement, citing eye-witness accounts of seeing police throw concussion grenades, 'the lack of charring of flesh at the wound site' and 'grenade pieces that have been removed from her arm in surgery and will be saved for legal proceedings'.

During September 2014, the Standing Rock Sioux Tribal (SRST) council met with Energy Transfer representatives for an initial consultation, which was more than a month before the pipeline's first formal submission to the Army Corps.

[93] The alternative selected by the Corps of Engineers crosses underneath the Missouri River, half a mile (800 m) from the Standing Rock Indian Reservation, and parallels the existing Northern Border Pipeline.

Noting that the water system serving Fort Yates on the Standing Rock Reservation was only 10 miles (16 km) downstream of where the pipeline would cross Lake Oahe and the Missouri River, the EPA recommended that the Army Corps revise its Environmental Assessment and open up a second public comment period.

By late September, NBC News reported that members of more than 300 federally recognized Native American tribes were residing in the three main camps, alongside an estimated 3,000 to 4,000 additional pipeline resistance demonstrators.

In recent days, we have seen thousands of demonstrators come together peacefully, with support from scores of sovereign tribal governments, to exercise their First Amendment rights and to voice heartfelt concerns about the environment and historic, sacred sites.

[118] Craig Stevens, spokesman for the MAIN Coalition, a labor group, called the Corps's announcement "yet another attempt at death by delay" and said the Obama administration "has chosen to further fan the flames of protest by more inaction."

[124] On February 8, 2017, the U.S. Army Corps of Engineers (USACE) granted Dakota Access, LLC an easement based on the Mineral Leasing Act to cross Lake Oahe and finish construction of the pipeline.

On February 9, 2017, the Cheyenne River Sioux Tribe filed a motion for a restraining order citing Religious Freedom Restoration Act violations, claiming an oil spill would disrupt their ability to worship freely.

The motion asked the Court to rule on unresolved legal questions concerning USACE, including the meeting of National Environmental Policy Act (NEPA) requirements and the violation of Tribal treaty rights.

[125][126] On June 14, 2017, Federal Judge James Boasberg issued his third opinion in the matter, ruling that the Corps permits authorizing the pipeline to cross the Missouri River "substantially complied with NEPA in many areas" but did not adequately consider certain aspects of the law.

According to a report published by Earthjustice, a non-profit public interest law organization dedicated to environmental issues: The Court ordered the Corps and DAPL to work with the Tribes to complete oil spill response plans at Lake Oahe.

The judge who heard Red Fawn's case did not allow her defence team to cite her treaty rights or "other issues related to her arrest at anti-pipeline protests near the Standing Rock Sioux's Tribe's reservation border.

It’s something we have to do, and we’re going to be met with this violence from these agencies, from the federal government, from the state.” [136] On August 11–12, 18 more people were arrested, including Standing Rock Tribal Chairman David Archambault II who was charged with disorderly conduct.

[154] The lawsuit alleged Greenpeace USA misled the public with false claims about the Standing Rock Sioux tribes' sacred sites and the likelihood the pipeline would contaminate the Missouri River in North Dakota.

It is also a check on corporate efforts to silence dissent.”[156] The Intercept online newspaper earlier reported Energy Transfer Partners hired the private security firm of TigerSwan to gather information for the lawsuit via fake social media accounts and infiltration of protest camps.

The mayor of Seattle and city council members joined leaders from Northwest tribes from Quinualt, Makah, Lummi, Suquamish, Tulalip, Swinomish, Puyallup and others to show opposition to the pipeline.

[173] Tara Houska, Director for Honor the Earth, spoke at a rally in New York City saying, "Because of the power of social media and the millions of those at Standing Rock, the Army Corps are going to invite the tribe in to discuss their concerns.

Some criticized a group of young, mostly white, people at the protest for treating it like a festival such as Burning Man by bringing drugs and alcohol, requiring supplies and provisions rather than sustaining themselves, or performing unsolicited live music.

[196] In December 2016, Klein, writing an editorial in The Nation shortly after the Army Corps of Engineers had turned down the permit for the Dakota Access Pipeline to be built under the Missouri River, said, "The Lesson from Standing Rock: Organizing and Resistance Can Win."

"[197] However, calling the Army Corps of Engineers request for further study an "incredibly cumbersome, long, horrible permitting process," on January 24, newly elected President Donald Trump signed a presidential memorandum to advance the construction of the pipeline.

[209] Several members of the House made statements as well, and Representative Tulsi Gabbard of Hawaii announced plans to join hundreds of other military veterans in protecting the protesters in early December.

[209] Native American lacrosse players Lyle Thompson and his brothers Miles, Jeremy and Hiana and others including Bill O'Brien and Scott Marr, used social media to support the protesters.