Vela Molecular Ridge is a molecular cloud complex in the constellations Vela and Puppis. Radio 12CO observations of the region showed the ridge to be composed of several clouds, each with masses 100,000–1,000,000 M☉. This cloud complex lies on the sky in the direction of the Gum Nebula (foreground) and the Carina–Sagittarius Spiral Arm (background). The most important clouds in the region are identified by the letters A, B, C and D, and in fact belong to two different complexes: the clouds A, C and D are located at an average distance of about 700-1000 parsecs (2300-3300 light years) and are related to the OB association Vela R2, while cloud B is located at a greater distance, up to 2000 parsecs (6500 light years) away, and is physically connected to the extended Vela OB1 association.