Okay - a few things to correct here in the Croatia/Bosnia area.
Belovar in Croatia is both a misspelling of Bjelovar, and 400 years out of date - it was founded in 1756 as a military town by the Habsburgs. The nearby town of Križevci is one of the oldest towns in Croatia, and is conspicuously absent - I'd replace it here.
Visoki, the historical centre of the Bosnian Kingdom is also conspicuously absent - I would rename the location of Vrhbosna or Zenica for it, depending on your preference.
As a province Krajina is anachronistic - the term literally means "borderland" or "frontier", and refers to the historically Croatian areas the Ottoman Empire conquered. Bihać and Srb were key centres of the Kingdom of Croatia, and would only become associated with Bosnia once this region was islamised under the Ottomans. I would include these two locations in the Lika province and the Croatia area accordingly.
The other three locations in the Krajina province, as well as Glaž correspond roughly to the three small border counties of Dubica, Sana, and Vrbas, administered with the Kingdom of Slavonia. Bosnia would only begin expanding to the northwest under Tvrtko I, who was crowned in 1353, after the start date, so Bosnia shouldn't control Kozara or Glaž in 1337. I would include Dubica in the Podravina province as Bosnia never conquered it, and Kozara and Gradiski Brod in the Donji Kraji province to reflect its historic enlargement as a Bosnian fief.
Bosnia should also at this time include Makarska, with Stephen II establishing a coastline for his fledgling polity around this start date.
Additionally I'd replace Szluin with Modruš and include it within Croatia rather than Slavonia, as it was an important political and episcopal centre in Northern Croatia at this time.
Here are a few maps that may prove helpful:
A map illustrating Sana, Dubica, and Vrbas counties:
A map showing the timescale and extent of Bosnian expansion - in 1337 it should reflect the medium salmon colour.
A map of historical Bosnian lands - the main divisions of the medieval kingdom. Note the expansion of Donji Kraji into Sana and Vrbas but not Dubica, and the lack of expansion into Bihać.
Belovar in Croatia is both a misspelling of Bjelovar, and 400 years out of date - it was founded in 1756 as a military town by the Habsburgs. The nearby town of Križevci is one of the oldest towns in Croatia, and is conspicuously absent - I'd replace it here.
Visoki, the historical centre of the Bosnian Kingdom is also conspicuously absent - I would rename the location of Vrhbosna or Zenica for it, depending on your preference.
As a province Krajina is anachronistic - the term literally means "borderland" or "frontier", and refers to the historically Croatian areas the Ottoman Empire conquered. Bihać and Srb were key centres of the Kingdom of Croatia, and would only become associated with Bosnia once this region was islamised under the Ottomans. I would include these two locations in the Lika province and the Croatia area accordingly.
The other three locations in the Krajina province, as well as Glaž correspond roughly to the three small border counties of Dubica, Sana, and Vrbas, administered with the Kingdom of Slavonia. Bosnia would only begin expanding to the northwest under Tvrtko I, who was crowned in 1353, after the start date, so Bosnia shouldn't control Kozara or Glaž in 1337. I would include Dubica in the Podravina province as Bosnia never conquered it, and Kozara and Gradiski Brod in the Donji Kraji province to reflect its historic enlargement as a Bosnian fief.
Bosnia should also at this time include Makarska, with Stephen II establishing a coastline for his fledgling polity around this start date.
Additionally I'd replace Szluin with Modruš and include it within Croatia rather than Slavonia, as it was an important political and episcopal centre in Northern Croatia at this time.
Here are a few maps that may prove helpful:
A map illustrating Sana, Dubica, and Vrbas counties:

A map showing the timescale and extent of Bosnian expansion - in 1337 it should reflect the medium salmon colour.
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A map of historical Bosnian lands - the main divisions of the medieval kingdom. Note the expansion of Donji Kraji into Sana and Vrbas but not Dubica, and the lack of expansion into Bihać.
.jpg)
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