Petrohan Pass is a mountain pass at an elevation of 1.444m (4,738ft) above the sea level, located in the Balkan Mountains in Bulgaria. The pass is traversed by the Road 81.
The asphalted road on the pass connects Sofia and Montana. This road is usually open all year, but it can be closed anytime when the access is not cleared of snow. It’s the shortest route between Sofia and north-western Bulgaria (and from there Romania). Heavy snowfalls can sometimes block some sections of the road and can be extremely dangerous due to frequent patches of ice. There are plans to improve the road and build a tunnel. Chinese investors are interested in building the tunnel under Petrohan and in expanding the existing highway. A tunnel under Petrohan pass will shorten the Lom-Sofia road by 70 km.