strong·hold 
/ˈstrɑ:ŋˌhoʊld/ noun
plural strong·holds /ˈstrɑ:ŋˌhoʊld/ noun [count] 1 : an area where most people have the same beliefs, values, etc. : an area dominated by a particular group
▪ The area/district/state is a Republican stronghold. 2 : a protected place where the members of a military group stay and can defend themselves against attacks
▪ The rebels retreated to their mountain stronghold. 3 : an area where a particular type of uncommon animal can still be found
▪ the last stronghold of the endangered deer
▪ The area/district/state is a Republican stronghold.
▪ The rebels retreated to their mountain stronghold.
▪ the last stronghold of the endangered deer
