The 291 gallery first displayed Georgia O’Keeffe’s abstract drawings publicly in 1916.
The gallery, formally known as Little Galleries of the Photo-Secession and commonly called 291, was operated by Alfred Stieglitz at 291 Fifth Avenue in New York. It was a crucial venue for introducing European modernism and experimental American art to U.S. audiences.
Anita Pollitzer showed O’Keeffe’s charcoal drawings to Stieglitz, who exhibited them at 291 in 1916. The display was made without O’Keeffe’s initial permission, but it marked her entry into the New York art world and led to a long professional relationship with Stieglitz.
The answer is not the Armory Show, which took place in 1913 and introduced many Americans to European modern art but did not mark O’Keeffe’s first public exhibition of these drawings. The gallery’s name is usually written as 291, after its street address.