Jani Jaha Oliver's legal guardian reported him missing Monday.
Police said they tracked Oliver's mother's debit card to a Maryland hotel. They said that both Oliver and his mother were in custody and were fine.
There was no word on when Oliver will return to Fayetteville.
The boy's biological mother is identified as Joy Maureen Oliver, 47. Police said the woman surrendered her parental rights in 1996. They also said she suffers from depression and has been without medication.
Oliver faces an arrest warrant in North Carolina on child-abduction charges and is being held until extradition. The boy is in the custody of the Harford County Department of Social Services.