Sheriff Chad Clary said Angel Davis and Brandon Flores-Craine, both 16 years old, ran away on Sunday, March 30. He said Flores-Craine is from Doniphan and Davis recently lived in Troy.
According to Davis' sister, Alaina Davis, the teens were last seen Sunday afternoon on a back road in Doniphan headed towards Atchison.
Clary said they left on foot and he is not sure if they have managed to find a ride with someone or if they are still in the area.
"It's like trying to find a needle in a haystack," he said.
The sheriff's office said they have not been able to track cell phones either.
Alaina said the teens took a green two-person tent with them and that her sister, Angel, was also carrying a blue drawstring bag and a blue duffel bag.
Clary said he does not believe the teens are in danger, but he has notified law enforcement agencies in Atchison, Brown and Buchanan Counties to be on the lookout for the teens. Anyone with information is asked to contact authorities.