The easement would clear the way for Energy Transfer Partners, which owns the pipeline, to complete drilling under Lake Oahe.
Labor for Standing Rock, an organization that includes some union workers who formerly worked on the pipeline, is participating in the march.
The Army Corps of Engineers may reach a decision over the approval of construction on the Dakota Access Pipeline as soon as Friday.
The chief executive of Phillips 66 said on Friday he expects the Dakota Access Pipeline to start operations in the second quarter, even though the project - which has sparked protests by Native Americans and environmentalists - is still in the midst of legal battles and a U.S. regulatory review. "The discord we have seen regarding the Dakota Access Pipeline doesn't serve the tribe, the company, the corps or any of the other stakeholders involved".
Thousands of people are expected to demonstrate in downtown Los Angeles Sunday against President Donald Trump's executive order fast-tracking the Keystone XL and Dakota Access oil pipelines, organizers said.
The pipeline runs about a half-mile from the reservation of the Standing Rock Sioux, which has fought the project.
Protesters converged previous year by the thousands onto makeshift camps near Cannon Ball, North Dakota, in an effort to stop the oil pipeline over concerns about native relics, water quality and climate change.
The new Army Corps decision is likely to invite new litigation from the tribe.
"The Obama administration correctly found that the tribe's treaty rights needed to be respected, and that the easement should not be granted without further review and consideration of alternative crossing locations", he told the Associated Press.
Tribal attorney Jan (yahn) Hasselman says the government "will be held accountable in court". The company has said it is safe.