The N-521 is a Highway in western Spain. It runs from the Portugal border to the Autovía A-5.

National road N-521 shield}}
National road N-521
Carretera nacional N-521
Major junctions
FromTrujillo
ToPortuguese frontier
Location
CountrySpain
Highway system

It starts at the border in the Sierra de São Mamede overlooked by the castle and hill top village of Marvão where it becomes the N-246 and then IP-2 to Lisbon.

The first town in Spain is Valencia de Alcántara it crosses the Alburrel River then the wooded Sierra Brava and Sierra de San Pedro. It then follows the Salor River to Cáceres and a junction with the N-630 which is overlooked by La Virgen de la Montaña. The road then crosses the plain to Trujillo with the Tamuja River. At Trujillo the road meets the Autovía A-5, junction 253 km.