Green Valley is a region on Mars within Vastitas Borealis that was chosen as the landing site of NASA's Phoenix lander.

It came from the decision process by which it was selected as Phoenix's landing site: prospective landing areas were color-coded based on how hazardous they were, with red being most hazardous through yellow to green being the safest.

[1] Green Valley has relatively few of the large boulders that could have tipped the lander if it had hit one during touchdown.

[1] During the local winter as much as three feet of carbon dioxide ice is expected to appear on the surface.

[3] Shortly before Phoenix's scheduled landing, the Mars Reconnaissance Orbiter photographed a pair of kilometer-tall dust devils in the Green Valley area.