Which Georgia O'Keeffe painting features a large white skull against a blue sky?

Georgia O'Keeffe's painting featuring a large white skull against a blue sky is Cow's Skull: Red, White, and Blue.

O'Keeffe painted the work in 1931 after collecting animal bones in New Mexico. A cow skull dominates the vertical composition, with the American flag's red, white, and blue colors echoed in the title and visual arrangement. The image joins a Southwestern object to a distinctly American color scheme.

The painting belongs to O'Keeffe's broader series of bone pictures. She often found bones in the desert and treated them as durable, sculptural forms rather than merely as symbols of death. Their bleached surfaces, holes, curves, and sharp edges allowed her to explore shape and space in ways related to her flower paintings.

The painting is sometimes mixed up with Ram's Head, White Hollyhock—Hills, another New Mexico work involving a skull. The species named in this title is decisive: it is a cow's skull, not a ram's head.