Jerma

Jerma
The Erma Gorge, Bulgaria
Native name	Јерма, Ерма
Country	Serbia, Bulgaria
Basin features
Main source	near Lake Vlasina, Serbia
River mouth	Nišava near Pirot, Serbia
Physical characteristics
Length	74 km (46 mi)

Coordinates: 43°4′0″N 22°41′7″E / 43.06667°N 22.68528°E / 43.06667; 22.68528

The Jerma (Serbian: Јерма) or Erma (Bulgarian: Ерма) is a river in southeastern Serbia and western Bulgaria. Even though not very long (74 km), it is notable for passing the Serbian-Bulgarian border twice.

The Jerma originates in the undeveloped and sparsely populated area of Krajište, in the southeastern corner of Serbia. Starting from the area between the artificial Lake Vlasina and the Bulgarian border, it flows to the northwest on the eastern slopes of the Gramada mountain, passing through the village of Klisura, after which it enters the area of Знепоље (Znepolje, Bulgarian: Знеполе, Znepole), an arid region stretching over the border into Bulgaria. This is where the Jerma crosses the border for the first time, at the border crossing of Strezimirovci.

Continuing through the Bulgarian part of Znepole curving around the eastern side of the Ruy mountain, the river, now called Erma, is also known as Transka reka after the town of Tran, a regional centre of this area. The Erma passes close to the villages of Glavanovtsi and Turokovtsi, where it turns north, running through Tran. After Tran, the Erma cut the famous gorge Transko zhdrelo ("Gorge of Tran"). After the gorge, Erma flows through the Bulgarian part of the village of Petačinci. Erma receives its major tributary, the Yablanitsa, right before it re-enters Serbia after a 26 km travel through Bulgaria. The river crosses the border for the second time about a kilometer after Petachinci.