Koznitsa ( bg, Козница ) is a railway tunnel under the Koznitsa ridge in the

Stara planina The Balkan mountain range (, , known locally also as Stara planina) is a mountain range in the eastern part of the Balkan Peninsula in Southeastern Europe. The range is conventionally taken to begin at the peak of Vrashka Chuka on the border betw ...

(Balkan Mountains), the longest tunnel in

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...

. The tunnel is located between the Bulgarian railway stations of

Koprivshtitsa Koprivshtitsa ( bg, Копривщица, pronounced , from the Bulgarian word , ''kopriva'', meaning "nettle") is a historic town in the Koprivshtitsa Municipality in Sofia Province, central Bulgaria, lying on the Topolnitsa River among the S ...

and

Stryama The Stryama ( bg, Стряма , known in Antiquity as ''Syrmus'') is a river in southern Bulgaria, an important left tributary of the Maritsa. The river is 98.7 km long and has a drainage basin of 1,490 km2. The Stryama has its source ...

and is 5,808 m long.

References

Railway tunnels in Bulgaria {{Europe-tunnel-stub