An 11-year-old Colorado boy disappeared after leaving his house to visit a friend, authorities said.

Gannon Stauch was last seen walking out of his Colorado Springs home on Jan. 27 when he told his stepmother that he was headed to a friend’s house, the El Paso County Sheriff’s Office said.

The boy was initially categorized as a runaway, but investigators later upgraded it to an endangered missing person’s case when they learned he relied on prescribed medication, Sgt. Deborah Mynatt told The Post.

On Sunday, more than 50 people, including agents from the FBI’s Child Abduction Rapid Deployment team, searched the Lorson Ranch section of Colorado Springs, where Gannon lives.

The hunt was shifted some 6 or 7 miles away on Sunday to an area near the El Paso County Jail, Mynatt said, declining to elaborate. The search remained ongoing early Monday.

Gannon was last seen wearing a blue jacket, blue jeans and tennis shoes. Investigators have been flooded with 134 tips about his disappearance as of Sunday, according to officials.

“I’m so thankful for the all the outpouring of help this case has brought,” Gannon’s biological mother, Landen Hiott, told reporters on Friday, ABC News reported. “My son is a very loving kid, he wouldn’t want to harm anybody at all and it’s so hard to think, ‘Why is this happening to him?’ I have no clue.”

Investigators have not said whether Gannon ever made it to the friend’s home, the Colorado Springs Gazette reports.

The boy’s biological father, Al Stauch, was out of town for training with the National Guard when Gannon vanished, he told KOAA.

“We kind of do the streetlight rule,” Stauch told the station. “When the streetlights come on or it gets dark, they better be home and it was like maybe 30 minutes past that. Started to worry at that point. Then I started texting all the friends that we know he goes to and nobody had seen him.”

Anyone with information about Gannon’s whereabouts is asked to call the El Paso County Sheriff’s Office at (719) 520-6666.