The strip ran in the Boston Post‘s Sunday comics section, always an oddball section in general. The Post always reserved at least one page for locally produced strips, of which Mary Ann was the longest and most faithfully appearing.
Adventures of Mary Ann first appeared on February 6 1921, initially as a half page strip. Two years into the run the strip was demoted to about quarter page size, a format that worked perfectly well for the simple, slightly amateurish art. By the late 20s Mary Ann was further miniaturized to the format seen above, about the size of a daily strip.
I know that the strip lasted until at least 1942, the last samples I have on hand, and it may well well have lasted a few years longer. I doubt that it made it past the war. So I have a little more research to do on this oddball, but the important question that I’ve been unable to answer is who the heck is M.H., and why did s/he remain anonymous all those years?