Georgia O'Keeffe had her first solo exhibition in 1917 at Alfred Stieglitz’s gallery, 291.
The gallery was originally called the Little Galleries of the Photo-Secession and was located at 291 Fifth Avenue in New York City. Its address became its familiar name: 291. Stieglitz used the space to present photography and European and American modern art.
O'Keeffe’s first solo exhibition there featured drawings and watercolors made during her teaching years in Texas and Virginia. The show established her connection with Stieglitz, who became her husband in 1924 and an important promoter of her work.
Stieglitz later operated other galleries, including the Intimate Gallery and An American Place. Those names belong to later phases of his career, so they should not be substituted for 291 when identifying O'Keeffe’s first solo show.