As I just read some of Carl Barks’s Duck comics and I have an interest in locating fictional places, let’s take a look at Donald Duck’s hometown. While Barks originally claimed his hometown was Burbank, where the Disney Studios are located, he later changed this to the fictional city of Duckburg. According to this website, the change might have been made because some stories needed a climate quite different from that of Los Angeles in order to work. Eventually, Barks established that Duckburg is located in the state of Calisota, on the Pacific coast. Don Rosa, who had an interest in establishing a consistent continuity for Barks’s stories, placed Duckburg about where the real-life city of Eureka, California is located.
Duckburg is the location of Scrooge McDuck’s money bin, and is near Grandma Duck’s farm. The official history of the place, as stated by Rosa based on material by Barks, is that Duckburg stands where Sir Francis Drake (a famous person whose name didn’t have to be changed at all to make him a duck) established Fort Drake. Later, it was acquired by Cornelius Coot, Donald’s ancestor, who changed the name to Duckburg. And it was Scrooge’s making his home there that led to its becoming a thriving metropolis. DuckTales is also centered in Duckburg, basing much of its design on the comics, although I don’t know that the city’s history ever played much of a part on the show.
Since Darkwing Duck was a spin-off of DuckTales, it presumably takes place in the same universe, and indeed it’s been stated that St. Canard is across Audubon Bay from Duckburg.
As far as other Disney Afternoon cartoons went, TaleSpin seemed to take place in its own world where the United States as such didn’t exist, and Chip ‘n’ Dale: Rescue Dangers occurred in the human world (despite the fact that Chip and Dale were introduced in the first place as foils for Donald). Goof Troop‘s Spoonerville might well have been in Calisota, or at least in the same world as Duckburg, but I couldn’t say for sure as I didn’t watch that show anywhere near as much.
While the Ducks’ world is the same as ours in most respects, there are a few differences. Of course, Calisota existing at all is one of these, and the stories mix fictional locations with real ones. There’s also the fact that most of the inhabitants are anthropomorphic ducks or the weird dog-men, with occasional other animals showing up as well.
I have read that Barks drew some of his characters as regular human beings, but it was rare. As far as the television cartoons goes, there was a Darkwing Duck episode where the title character was sucked into our world, and declared its inhabitants to be “hideous beakless mutants.”