The three defendants entered their pleas during a hearing before U.S. Magistrate Judge Mark Carman at the Yellowstone Justice Center in Mammoth Hot Springs on Thursday.
Four of the High on Life group were originally charged with disorderly conduct by creating a hazardous condition and foot travel in a thermal area in Yellowstone.
The attorney for the High on Life defendants and federal prosecutors want to settle all the charges against the defendants in federal court in Mammoth Hot Springs.
The defendants and their Vancouver, B.C.-based High on Life/SundayFundayz have drawn international outrage for posting videos of unethical if not illegal behavior at national parks and international sites.
Besides posting their behavior at Yellowstone on social media sites, the four men with High on Life have done so with them behaving unethically if not illegally at the Bonneville Salt Flats and the Berlin Holocaust Memorial.
The Assistant U.S. Attorney said he would like to have all the cases resolved as one, but that may not be possible. The next status conference with the court is Aug. 8.