The first theatrical screenings of the film were in St. Louis in December of 1942. Showtimes were listed in several St. Louis newspapers during that month and a review of the film ran in the St. Louis Star and Times on December 5th, 1942.

https://www.newspapers.com/search/#query=ox-bow+incident&s_place=St.+Louis%2C+MO&dr_year=1942-1942