A geographical and historical region located between the Nestos and Maritsa rivers in northeastern Greece. The approximate area of Western Thrace is 8,578 km².

Geographically, it is bordered by the Nestos River to the west, the Maritsa River to the east, the Aegean Sea to the south, and the Rhodope mountain range to the north.

The terrain of Thrace is characterized by long mountain ranges, coastal plains, and major rivers flowing through the region. The largest rivers are the Nestos and the Maritsa, originating from Bulgaria, crossing Greece, and forming a delta as they flow into the Aegean Sea. The most significant lake is Lake Vistonida, located on the borders of Xanthi and Rhodope provinces. The coastlines are smooth, sandy, and mostly suitable for swimming. The only island in the region is Samothrace.

The climate differs from the rest of Greece. In winter, temperatures drop significantly in mountainous areas due to northern and northwestern winds. Rainfall is twice as much as in plains, and snow is significantly higher, often not melting until mid-spring. Coastal regions have a clearly milder climate, typically with Mediterranean characteristics; summers are hot and dry, while winters are rainy. In the peaks of large mountains and especially in the border mountains, the climate is harsh/continental; winters see heavy snowfall, and summers are cool with sudden thunderstorms.