Here are the area numbers of every 5 Kingdoms in matter of quantity of land inside the berm :
Le Parc Disneyland : 140 Acres (566,560 M2)
Tokyo Disneyland : 115 Acres (465,388 M2)
Magic Kingdom : 107 Acres (433,000 M2
Hong Kong Disneyland : 100 Acres (404,685 M2)
Disneyland Park : 85 Acres (344,000 M2)
Now beside Disneyland, not every square meters of those aera numbers are occupied by the park. Walt Disney World’s Magic Kingdom holds in its berm a large unoccupied surface, so does, in smaller figures Disneyland Paris and Hong Kong Disneyland.
We can also say, that beside its most modest enterprise : Hong Kong Disneyland, Disney always increased the size of its Magic Kingdoms over the years.
I know that HKL and the MK are all able to go beyond the current berms if needed. What about DLP and TDL? Are they landlocked like DL?
No they’re not landlocked, TDL’s berm is 1/3 boarded by OLC owned parking areas that could be used if they added another mutli-level parking building.
Not planned though :p
As for Disneyland Paris though they could only grab a few acres where toontown was supposed to be build and another small piece of land where Buzz Lighyear Pizza Planet has been hurrily assembled years ago. DLP could only add 2 maybe 3 attractions outisde its berm, as TDL, doing a bit of landscaping could easily add a whole land