OK - here’s the active duty divisions, and locations. So most likely the 3 located in the USA lower 48? Would that many men be needed? Waiting for comment from FReeper Marines.
Official Name
Insignia
Headquarters
1st Marine Division
Marine Corps Base Camp Pendleton
California
2nd Marine Division
Marine Corps Base Camp Lejeune
North Carolina
3rd Marine Division
Marine Corps Base Camp Smedley D. Butler
Okinawa, Japan
4th Marine Division
New Orleans, Louisiana
https://en.wikipedia.org/wiki/List_of_United_States_Marine_Corps_divisions
18
Only ones needing ‘activation’ are the 4th, MARFORRES. Marine Forces Reserve. Units/personnel nationwide.