December 2014: Energy Transfer Partners LP applies to build a 1,172-mile, 570,000 barrel-per-day pipeline to deliver crude oil from North Dakota's Bakken shale fields to Patoka, Ill., crossing South Dakota and Iowa to the North Dakota Public Service Commission, kicking off a year of public hearings in the state.
January 2016: North Dakota regulators approve the pipeline unanimously
April 29: U.S. Army Corps of Engineers holds a hearing for Native Americans on the pipeline. There was near unanimous opposition to the project, according to local media reports.
July 25: The U.S. Army Corps of Engineers approved three easements for water crossings for the pipeline at Sakakawea, the Mississippi River and Lake Oahe. Lake Oahe is an ancestral site for the Standing Rock Sioux tribe.
July 27: The Standing Rock Sioux Tribe sues the U.S. Army Corps of Engineers in the U.S. District Court of the District of Columbia in connection with the pipeline, citing violation of multiple federal statutes that authorize the pipeline's construction and operation, and seeks an emergency order to halt construction. The tribe also alleges the pipeline threatens their environmental and economic well-being and would damage and destroy sites of historic, religious and cultural significance. The Sioux Tribe say that because the pipeline goes underneath Lake Oahe, approximately half a mile upstream of the tribe's reservation, leaks from the pipeline would be directly in the tribe's ancestral lands.
Aug. 24: Celebrities including Susan Sarandon, Riley Keough and Shailene Woodley joined members of the tribe outside a courthouse in Washington, D.C., to protest the pipeline saying that it could pollute water and desecrate sacred land.
Sept. 3: Private security guards hired by Energy Transfer Partners used attack dogs and mace after violence erupted at a private construction site along the pipeline route. Six people were reportedly bitten by dogs, a scene that was captured on video and broadcast widely.
Sept. 6: Brian Cladoosby, president of the National Congress of American Indians, which represents more than 500 tribes, spoke to nearly a dozen of President Barack Obama's Cabinet-level advisers at a meeting of the White House's three-year-old Native American Affairs Council. Cladoosby delivered an impassioned request to his audience: stand with Native Americans who have united with the Standing Rock Sioux tribe and block construction of the Dakota Access Pipeline.
Sept. 9: U.S. District Judge James Boasberg in Washington rejected a broad request from Native Americans to block the project. He, however, rules that no construction activity on the Dakota Access may take place between Highway 1806 and 20 miles to the east of Lake Oahe. Construction activity to the west of Highway 1806 may proceed. The tribe appeals the decision.
Sept. 9: Less than an hour after Boasberg's decision, the U.S. Justice and Interior Departments and Army made an unprecedented move and ordered a stop to construction near Lake Oahe until the Army Corps of Engineers reviews its previous decisions and decides if it needs to conduct a fuller environmental and cultural review.
Sept. 13: Energy Transfer Partners told employees in a letter, provided to media, that the company was committed to completing the project. The midstream operator cited that the pipeline was 60 percent complete, and that it had already spent $1.6 billion so far on equipment, materials and the workforce.
Oct. 9: The U.S. Court of Appeals of the District of Columbia Circuit said that an administrative injunction related to the emergency motion of the Standing Rock Tribe would be dissolved, citing that Dakota Access has rights to construct on private land up to Lake Oahe.
Oct. 11: Environmental activists across four states disrupted the flow of millions of barrels of crude from Canada into the United States in a rare, coordinate action that targeted several key pipelines simultaneously. The protest group, the Climate Direct Action, said their move was in support of the Standing Rock Sioux Tribe. As a safety precaution, companies operating the pipelines shut off sections of the lines for several hours while they investigated. Earlier in the day, Energy Transfer Partners said it looked forward to prompt resumption of construction activities east and west of Lake Oahe on private land.
Oct. 25: Government-to-government tribal consultations began across six regions on how federal government decision-making on infrastructure projects could better include tribal concerns.
Nov. 8: Energy Transfer Partners says it has built the pipe to the edge of Lake Oahe and reiterates its intentions to complete the project.
Nov. 9: Following the surprise victory of Donald Trump in the U.S. presidential election, climate activists and the Standing Rock Sioux say they still hope President Obama will be able to kill the pipeline definitively. Analysts say the line is more than likely to go through.
Nov. 14: The U.S. government, in a joint notice issued by the Department of the Interior and the Army Corps of Engineers, delayed a final decision on permitting. They said the permit had followed all legal requirements, but said more consultation with Native American tribes was needed.
Nov. 18: Energy Transfer Partners' CEO Kelcy Warren told the Associated Press that the pipeline would not be re-routed. The statement came as protests grew more heated.
Reporting by Catherine Ngai and Valerie Volcovici/Reuters