Alfred Stieglitz's New York gallery that showed O'Keeffe's work was called 291.
The gallery took its name from its address at 291 Fifth Avenue in Manhattan. Stieglitz founded it in 1905 with Edward Steichen, originally as the Little Galleries of the Photo-Secession. It later became widely known simply as 291.
The space championed photography and European modern art, making it an influential meeting point for avant-garde culture in the United States. Stieglitz exhibited O'Keeffe's abstract drawings there in 1916, giving her work an important early platform.
A common mix-up is to treat “291” as a work title or a shortened street address only. It was the gallery's recognized name. After 291 closed in 1917, Stieglitz continued promoting O'Keeffe through later galleries, including the Intimate Gallery and An American Place.