The Jerma or Erma is a river in southeastern Serbia and western Bulgaria. Even though not very long, it is notable for passing the Serbian-Bulgarian border twice.
Course
Serbia
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, 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.

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