Its administrative and economic center of the region is Postojna, while other minor centers include Logatec, Cerknica, Pivka and Ilirska Bistrica.
It stretched over the Postojna Gate to the hills south of Emona (today Ljubljana).
Until 1860, these sub-regions coincided with the districts (Kreise) of Ljubljana, Novo Mesto and Postojna.
At the time when Benito Mussolini was willing to modify the Treaty of Rapallo, which cut off a quarter of Slovene ethnic territory from the remaining three-quarters of Slovenes living in the Kingdom of SHS, in order to annex the independent state of Rijeka to Italy, Pašić's attempts to correct the borders at Postojna and Idrija were also undermined by regent Alexander preferring "good relations" with Italy.