A: San Francisco, California, United States
Agnes Peterson Founds The Women's Co-Operative Printing Union in San Francisco
Mae Silver, author of The Sixth Star, reproduced this advertisement for the Women's Co-operative Printing Union that was originally published in West Coast Journal, May 18, 1870. This I found in foundsf.org.
Probably the first woman-owned printing business in California was the Women's Co-Operative Printing Union founded in San Francisco in 1868. The advertisements that I reproduced with this entry were all the evidence that I had of this business in November 2020.
Patricia Keats, "Women in Printing & Publishing in California, 1850-1940," California History, 77 (1998) 93-97.