Bobby Rodgers, from Newtowncunningham, was a passenger in an Astra which crashed near Murlog on the Lifford to Letterkenny road on Sunday afternoon.
The driver and another passenger were taken to Letterkenny General Hospital where they are being treated for their injuries.
Mr Rodgers, a keen football fan, was hugely popular with many friends in east Donegal and Derry.
A former student at Deele College in Raphoe, friends described him as “bubbly” and “great fun.”
He was just 21.
One friend told us: “He was the funniest lad, just great fun and great to be around. We are all so gutted and are just thinking of his family now. It’s hard to take in.”
Another emailed us to say: “Bobby was one of the best; just a great fella who has gone far too soon. So many people will miss him.”
Garda Traffic Inspector Michael Harrison appealed for information on the incident and urged anyone who witnessed to contact gardai in Lifford or Letterkenny.