Polk is right. With Texas(268000 miles) and the Mexican Cessation, he added more territory( over 1000000 miles of territory) than any other president.
Here are the 8 presidents:
1. Polk(Mexican Cessation, Texas)
2. Jefferson(Louisiana Purchase)
3. Johnson(Alaska, Midway islands)
4. Madison(Florida)
5. Tyler(Northern Maine)
6. Filmore(Gadsen Purchase)
7. McKinley(Puerto Rico, Guam
8.Wilson(US Virgin Islands)
Your turn Malte.
Nick