The N-420 runs north through the heavily wooded Sierra Morena passing over the Puerto de Niella (902m) then crossing the valley of the Rio Montoro before taking the Puerto Pulido to Puertollano.
The N-420 travels north through the Sierra Morena, passing over the Puerto de Niella and crossing the Rio Montoro valley. It then reaches the Puerto Pulido and Puertollano.