They say they're afraid of the pipeline bursting and contaminating good drinking water.
"I'm the mother of three children", Espinoza said.
The Morton County Sheriff's Office, who have been policing the protests, North Dakota Governor, Republican Doug Burgum, and the state's US Attorney Chris Meyers also sought federal support.
President Trump has shown little sympathy for protesters of any sort, so we're wondering how he plans to react to protesters - will he try to move them off the land by force, or engage them in a dialogue on why he thinks this project should move forward?
"This demonstration will allow people to voice their concerns about the pipelines, which can leak and ruin natural resources", he added. President Barack Obama had vetoed the TransCanada Corp. project a year ago.
In December, the U.S. Army Corps of Engineers stopped construction of the pipeline to conduct an environmental impact review and determine alternative routes. The project was conceived almost a decade ago, but since then the US shale revolution has redefined oil flows, with domestic refiners finding themselves awash with supply and needing fewer imports.
The new 36-inch pipeline would run 1,179 miles from Hardisty, Alberta, to Steele City, Nebraska, where it would connect to pipelines to IL and to the Gulf Coast.
Trip Van Noppen, president of nonprofit environmental law organization Earthjustice, said in a statement that Trump "appears to be ignoring the law, public sentiment and ethical considerations" with the decision. "Looks like corporate America has struck again".
During the time the protesters were there, a man shouted from the passenger seat of a passing SUV, "Trump train. The fight has just begun". "Human life around the world", King said.
Cristina Yelvington said she believes uniting in protest can make a difference.