Noem said at her daily briefing that she has sent affidavits and video to the White House, the Department of Justice, the Interior Department and her state's congressional delegation, asking for help resolving the dispute.
“This is not taking sides. This is simply upholding the law,” the Republican governor said.
The tribes set up the checkpoints last month to keep unnecessary visitors off the reservations.
Earlier this month, Noem threatened to sue the Cheyenne River Sioux Tribe and the Oglala Sioux Tribe if they did not remove highway stops within 48 hours. She backed away from that plan last week, offering to negotiate on the issue if they would take them off of U.S. and state highways.
“I know there are questions out there about respecting (tribal) sovereignty,” Noem said Wednesday. But she contends the checkpoints cannot legally be on those highways.
Remi Bald Eagle, a spokesman for the Cheyenne River Sioux Tribe, said Wednesday he would seek Frazier's reaction to Noem going to the White House in the dispute.
Oglala Sioux president Julian Bear Runner, whose tribe is in the southwest corner of the state, did not immediately respond to requests for comment Wednesday.