Before it became the Garrick, the theater was the the Bijou. The Garrick building later became a Grant's department store. I believe the Garrick was gone by the early 1930's.
The Garrick Theater was located at 106 Broadway. To its north was the Black Building and to its south was the Globe Clothing Store (formerly the Holmes Clothing Store). The theater advertised in the December 1921 Fargo Forum, so it was at least that old.
Frank Treat was the owner. In a 1926 advertisement, the Garrick describes itself as the "home of the golden voiced Barton organ." The "cosy, popular priced" theater offered "high class photoplays."
In the postcard above, it appears that there is a double feature playing. James Hall and Marie Prevost, silent and sound movie stars from the 1920s and 1930s, appear. I cannot find any movie in which they appeared together.

Fargo, North Dakota
Garrick Theater