Today in the history of the American comic strip: June 30

American cartoonists and writers may not have invented the comic strip, but some argue that the comics, as we know them today, are an American creation. Clearly, the United States has played an outsize role in the development of this underappreciated art form.

6.30.1940: Dale Messick’s Brenda Starr, Reporter, makes its initial appearance. It remained in syndication until 2011, by which time Brenda had finally been promoted to an editor's job.

6.30.2015: Leonard Starr, the creator of Mary Perkins, On Stage, (originally titled On Stage), dies at 89. His strip ran from 1957 to 1979
 

Mary Perkins, On Stage

Most of the information listed here from one day to the next comes from two online sites -- Wikipedia, and Don Markstein's Toonopedia -- as well as 100 Years of American Newspaper Comics, edited by Maurice Horn. Note that my focus is on American newspaper comic strips (and the occasional foreign strip that gained popularity in the United States). Thus, comic books and exclusively online comics are not included here.