Alfred Stieglitz's New York gallery was known as 291.
The name came from its address at 291 Fifth Avenue in Manhattan. Stieglitz first operated the gallery as the Little Galleries of the Photo-Secession, but it became widely known by its address. The space introduced American audiences to photography and European modern art.
In 1916, Stieglitz exhibited drawings by Georgia O'Keeffe there after seeing them through the artist Anita Pollitzer. The exhibition helped bring O'Keeffe to the attention of the New York art world, even though she was still developing her independent career.
The gallery closed in 1917 because of financial difficulties and wartime conditions. Stieglitz later ran other galleries, including The Intimate Gallery and An American Place. Those later names should not be substituted for 291 when identifying the venue associated with O'Keeffe's first Stieglitz exhibition.