The group opposes the Keystone XL pipeline, a planned oil pipeline from Canada to the U.S. Gulf Coast. It would go through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas to refineries in Texas.
The protesters are calling for clean energy investments instead.
Hannah sat down on the sidewalk near the White House and refused orders from U.S. Park Police to move.
She has been arrested in the past for environmental causes.
The Associated Press contributed to this report.
