Today in the history of the American comic strip: July 1

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.

7.1.1944: Hilda Terry launches Teena, a revised version of her earlier strip, It’s a Girl’s Life. The cartoon ran until 1966.

7.1.1976: Rick Redfern makes his first appearance in Garry Trudeau's Doonesbury. An investigative reporter for The Washington Post, he eventually loses his job, after which his life takes some frustrating turns.

7.1.1979: Stan Lynde’s Latigo adds a Sunday page. The comic focused on the son of a mountain man and a Crow Indian who serves in the Union Army during the Civil War and later becomes a federal marshal. 

7.1.1996: Frumpy the Clown is syndicated. Created by Judd Winick, the cartoon involved a grumpy but child-friendly clown who moves in with a family after Brad Bragg, a 10-year-old boy, brings him home.
 

Latigo

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.