Calisota is a fictional U.S. state, created by Carl Barks in his story "The Gilded Man" (Four Color #422) and used in comic books produced by the Walt Disney Company. Duckburg is among the cities located there. Presumably, so are Goosetown, Mouseton, Spoonerville, and most likely St. Canard, since the Audubon Bay Bridge connects St. Canard to Duckburg.
Although it has many fictional elements and a variable climate, Calisota is probably roughly equivalent to Northern California. Duckburg has occasionally been said to be seated north of Los Angeles and San Francisco. A map in Don Rosa's The Life and Times of Scrooge McDuck shows that Calisota covers the part of California north of Sacramento. Its location roughly corresponds to the borders of the real-world proposed state of Jefferson.
The name is a blend of California and Minnesota — supposedly to allow all kinds of weather or climate in the stories, although Calisota bears very little in common with the latter (a state in the Upper Midwest, far from the ocean coasts.) It may also be a reference to Calistoga, a small town in Napa County, which is, like Duckburg, north of San Francisco.