Vastitas Borealis (Mars)

This feature is named after an earlier feature.

Vastitas Borealis is the largest lowland region of Mars. It is in the northerly latitudes of the planet and encircles the northern polar region. Vastitas Borealis is often simply referred to as the northern plains or northern lowlands of Mars. The plains lie 4–5 km below the mean radius of the planet. (wikipedia entry)

A vastitas is an extensive plain. On Mars they are named after the nearest named albedo feature on the Schiaparelli or Antoniadi maps.