How did geography influence Macedonia?

The Republic of North Macedonia is located in the northern part of the area traditionally known as Macedonia, a geographical region bounded to the south by the Aegean Sea and the Aliákmon River; to the west by Lakes Prespa and Ohrid, the watershed west of the Crni Drim River, and the Šar Mountains; and to the north by the mountains of the Skopska Crna Gora and the watershed between the Morava and Vardar river basins. The Pirin Mountains mark its eastern edge. The Republic of North Macedonia occupies about two-fifths of the entire geographical region of Macedonia. The rest of the region belongs to Greece and Bulgaria. Most people with a Macedonian identity also refer to the region that constitutes North Macedonia as Vardar Macedonia, the Greek part of Macedonia as Aegean Macedonia, and the Bulgarian part of Macedonia as Pirin Macedonia. In this article, unless otherwise indicated, the name Macedonia refers to the present-day state of the Republic of North Macedonia when discussing geography and history since 1913 and to the larger region as described above when used in earlier historical contexts