Police responded to a report from the ambulance service yesterday at about 8.45pm that a boy had been stabbed in the Woodham Burn area of Newton Aycliffe.
The location was a grassed track just off Stephenson Way close to the burn.
A 15-year-old local boy was taken by ambulance to the James Cook Hospital in Middlesbrough where he remains in a stable condition today. His injury is not believed to be life-threatening.
A local youth, also aged 15, was arrested at the scene and remains in custody at Bishop Auckland police station. He was due to be questioned about the incident today (Tuesday).
A number of people witnessed the incident and enquiries are ongoing.