The geographic factor was actually their location.
Prosperity.
Calvin Coolidge was in office as president from 1923 to the spring of 1929. In that period of the "Roaring Twenties," the country experienced great economic success -- in between the brief depression that followed World War I and the Great Depression that began with the stock market crash that occurred in the fall of 1929.
It would be Alaska
Size (land & water) (square miles) would be 663,267.26 in total so it is the biggest
What the passage supposed to be, we can’t see it