Nassau County Police said Steven Montalvo, 26, of Elmont, was found at the hospital at 5:36 a.m.
He was reported missing after he didn't show up at The Gathering Place in Hempstead where he had lat been seen heading at 8 a.m. Tuesday. He was wearing a Polo coat, blue jeans and black Nike sneakers.
Police could not immediately say how the 5-foot-10, 200-pound Montalvo ended up at the hospital nor could they say whether he had been injured.
The Silver Alert Program is used by several law-enforcement agencies nationwide to help find cognitively impaired persons who have been reported missing.