At the end of winter 1915, in February and March, the frontline stalled on the hill over village Sukov (dist. Medzilaborce) in the territory of nowadays north-east Slovakia. Part of the Austrian trenches was built in open terrain at mountain meadow. This position was occupied by Landwehr infantry regiments nr. 8 ( from Prague) and 9 ( from Písek). Presence of trenches on this place led to its quick erosion and disappearance in a short time after the war and today it is impossible to visually locate. This article presents experimental use of magnetometric survey for localisation of Austro-Hungarian trenchline from the First World War. It is the first use of geophysical methods for this purpose in this kind of territory.