Carson, new Homeland Security Secretary Kirstjen Nielsen and a handful of other federal officials managing disaster response were visiting the island for a one-day trip.
"You know, interestingly enough from the reports that I had gotten, I had no idea that we had moved this far along," Carson said, speaking to staff at the Federal Emergency Management Agency's Joint Field Operations Center near San Juan.
He reiterated the sentiment in a meeting with a smaller group of officials from FEMA, HUD and the Department of Homeland Security.
"I'm extremely impressed with the progress that's been made. It's better than what I had heard previously," Carson said. "And when I see the look in people's eyes ... it makes me even more determined to be with you to the very end."
Carson and Nielsen both made a point to repeatedly thank staff and officials on the ground for their efforts, and and they pledged to continue the rebuilding.
"This has been a tough season," Nielsen said. "We're six, seven months away from the next season, so we'll continue to work on preparedness while you continue the work you're doing here on recovery."
The secretaries were both making their first trip in their current roles, though Nielsen came once before during her role in the White House working with Chief of Staff John Kelly, and Carson's deputy had also been there previously. The pair had a full day of meetings with officials but did not tour the island, or visit or fly over the hardest-hit areas outside San Juan.
Recovery has been slow since the September hurricane. Though signs of progress are clearly visible in San Juan and greenery has returned, traces of destruction also clearly remain. Snapped trees and mangled debris are apparent throughout the city.
And though an Energy Department official said Tuesday that nearly 70% of the island's power generation capacity is back online, locals say that does not reflect the number of homes that are receiving power, as infrastructure remains damaged. The federal government says data on the number of residents receiving power is no longer available.
Carson pledged that his agency would see the recovery through to the end. As the emergency response transitions into recovery, HUD will begin to take on more responsibility as it distributes Community Block Development Grants for Disaster Recovery. The agency is waiting on FEMA to finish assessing needs on the island in order to set a total amount for those grants and then will offer guidance as they are spent.
"We are in this for the long haul," Carson told a group of six local mayors and vice mayors. "Early on, you'll see a lot of FEMA, but in the long haul, you'll see a lot of HUD. And we're going to be with you for the long haul. It's going to be very difficult but I've been so impressed but what I've seen already."