https://forgottenrealms.fandom.com/wiki/Cormyr

Example Cormyr

(2E) Population 1,360,800 (as of 1372 DR)^[4] 

Actual Assumed population is twice that for 2,721,600 in 5E   (Can support 5 Duchies, 50 Counties and 500 Baronies) 4 non Royal Duchies, 45 Counties and 450 Baronies in typical breakdowns.

https://forgottenrealms.fandom.com/wiki/Suzail

Capital: Suzail  55,000    (Duchy of the Crown)  (x5 normal businesses, economy and taxes)

Cities

https://forgottenrealms.fandom.com/wiki/Arabel

Arabel: population 30,000  (x3 normal businesses, economy and taxes)

https://forgottenrealms.fandom.com/wiki/Marsember

Marsember: Population 38,000  (x3 normal businesses, economy and taxes)

Settlements

https://forgottenrealms.fandom.com/wiki/Template:Category_intersection_jump?DPL_cat1=Locations_in__Cormyr&DPL_cat2=Settlements