THE 15-year-old boy who died after going into the River Roe was Steven Mitchell.
The emergency services were called to the Roe Valley Country Park in Limavady around 4.30 pm on Thursday.
It is understood the schoolboy went into the water to retrieve a ball, but got into difficulties.
Emergency services arrived and a PSNI helicopter airlifted him to Altnagelvin Hospital from an adjacent field.
However, it is believed he may have been in the water for some time and did not survive.
The part of the river where the incident happened is known as Givens weir and is accessible by foot only.
Stephen Mitchell is believed to be from Ballyclare, Co Antrim and was with his family at the time tragedy struck.
Local Limavady DUP councillor Alan Robinson said: “I’m led to believe that there was a young 15-year-old who had travelled down from somewhere on up the country who had been playing in the water.
“There was an incident. He was removed from the water and I’m told that he subsequently died later in hospital,” Mr Robinson said.
His party colleague, assembly member George Robinson, said the country park was a big tourist attraction, which people sometimes used for camping.
“Everybody here is devastated by what happened to that wee lad,” Mr Robinson said.
“I would appeal to people to be on their guard when they’re using the water in the soaring temperatures.”
New SDLP Environment Minister Mark H Durkan said the boy’s death was a “terrible tragedy” and that he had asked his officials for an urgent report on the incident.
“My heart goes out to the family of the teenager and I offer them and his friends my deepest sympathy,” he added.