While the specific time period is not explicitly stated, it's generally understood that the Nancy Drew books are set in the 1930s and 1940s, based on the style of writing, the cars, and the social context.
As for the location, "The Wide Window" takes place in the fictional town of River Heights, which is where most of the Nancy Drew books are set. It's located somewhere in the Northeastern United States, likely near a body of water, based on various mentions in the books.