Hours from Standing Rock, N.D., is another reservation, in the the Bakken oilfield's sweet spot. Drilling has brought in millions of dollars, but the tribes have environmental worries, too.
Many say the Dakota Access Pipeline resistance is beyond anything they've experienced before. But there are preludes in Native American history, and you don't have to look too far back to find them.
Pipelines are center stage in a fight over the nation's energy future, concerns about climate change and private property rights. Donald Trump's election means the battles are likely to continue.
At the Dakota Access Pipeline site, officers used pepper spray against demonstrators on government land. The protesters say the pipeline would violate sacred Indian lands and could cause pollution.
"There's an obligation for authorities to show restraint" in their handling of people protesting the Dakota Access Pipeline, President Obama said in an interview with the news organization Now This.
It's a show of support for the tribe that has been rallying against construction of the Dakota Access Pipeline, which the tribe says could contaminate drinking water and harm sacred lands.
Law enforcement in North Dakota arrested more than 140 on private land owned by the pipeline company. The Standing Rock Sioux Tribe wants to prevent the pipeline from running under the Missouri River.
Police officers, some of them in riot gear, removed protesters who refused to leave private land in North Dakota where a pipeline is supposed to be built.
Protests against the Dakota Access Pipeline have been raging. Tribe leader Dave Archambault II says he's telling supporters "not to react to any form of aggression that law enforcement brings."