Pete Mullaney has been looking through scans of the Washington Star for old comic strips and passed this one along.
Those Were The Happy Days! by Dick Mansfield is from the Washington Star January 7, 1940. Note the mentions of Washington Market, Hagerstown, and Alexandria, although most of the cartoon is generic reminiscences of the past. Today, the Post runs the similar Flashbacks strip by Patrick Reynolds, but that's produced in Pennsylvania.
Dick Mansfield was a DC police inspector though, and actually made it up to Hagerstown on occasion. Markus Ring (whom I knew, in the small world department) recalled the strip in 1997 although his memory placed it in the 1920s.