It connects with France at the Tunnel of Somport (12 km) with Huesca.

The road emerges again south of Teruel following the Rio Turia.

The N-420 branches west in the Rincón de Valencia rising to over 1,000m.

It then runs south to Utiel and the Autovía A-3 in the province of Valencia.

At Requena the road heads south again into the Sierra Martés with a junction with the N-322 and then crosses the Puerto de Cruz de Confrentes and then down to the Rio Xúquer.