"It is prudent to start this move now," said corrections department spokeswoman Alison Morgan. "It allows a systematic and methodical move."
Of the 905 inmates at Territorial, 24 were classified as a "specialized" population including some who were wheelchair-bound or reliant on oxygen tanks.
"We have medical and mental health, geriatric and hospice inmates," Morgan said. "They have walkers, oxygen tanks, canes, wheelchairs."
"Early in the evening we made the decision to move the 24 inmates in the infirmary including the hospice patients to Denver," she said.
The remaining 881 inmates were transferred to the Centennial Correctional Facility, which was decommissioned in 2012 but has been maintained in the interim.
Morgan said the transfer was accomplished overnight "with military precision" using four full-sized busses, accompanied by patrol cars and more than 100 staff from nearby prison facilities.
The Royal Gorge fire was burning only a few miles southwest of the Territorial facility, and has burned nearly 4,000 acres south of Denver.