Dreieckiger Pfahl

The Dreieckige Pfahl ("Triangular Post") is an historic boundary stone, about 1.35 metres high and made of granite, located southwest of the Brocken, the highest mountain in the Harz Mountains of central Germany. The stone, erected before 1866, marked the border between the Kingdom of Hanover and the Duchy of Brunswick. Originally this spot was a tripoint. During the division of Germany the border between the German Democratic Republic and the Federal Republic of Germany ran past the Dreieckiger Pfahl. Today it marks the border between the states of Saxony-Anhalt and Lower Saxony, the post lying just within the Lower Saxon side. During the Cold War it was accessible from the west.

The historic stone stands at an elevation of about 870 metres, around 2.5 kilometres east of a car park on the B 4 federal road between Torfhaus and Oderbrück.

The first recorded mention of a boundary stone being located here dates to the year 1727. On a map of the Upper Forest of Braunlage (Oberforst Braunlage) is the note "drey Eckjer Pfahl anno 1698". From a description of the Harzburg Forest (Harzburger Forsten) the original stone is described thus:

Solcher Pfahl ist auch nach Communion Seite zur linken Hand mit Nr. 1 und einer Wolfsangel, nach Braunlagischer Seite mit drey Hieben und auf Elbingeroder Seite mit Nr. 1 und einem Kreuz ingleichen mit der Jahreszahl 1698 gesetzt und hat dabei seinen Namen erhalten.

...which translates roughly as...

Such a post was also erected with a No. 1 and a wolfsangel inscribed on the left hand side facing Communion, three gashes on the Elbingerode side, and a No. 1 and a cross with the year 1698 inscribed on the Braunlage side; hence its name.

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Wikipedia