Gaisberg, Mountain summit in Heidelberg, Germany

Gaisberg is a 375.7 m high mountain in Heidelberg, the northwestern spur of the Königstuhl in the Kleiner Odenwald. Its elongated, flat summit is separated from the Königstuhl by the Sprunghöhe, a saddle about 30 m lower. Near the highest point stands the Gaisbergturm, and an arboretum with giant sequoias planted in 1876 lies around it.

The mountain's southwest flank was fortified in 1462, when Elector Frederick I built Trutzkaiser to guard Heidelberg's southwestern approach; rubble of the work still lies off the paths. In July 1622, General Tilly's imperial-Bavarian troops besieged Heidelberg and set up two field camps on the Gaisberg, one on the Sprunghöhe, to direct fire on the town and castle.

The name Gaisberg also appears on official maps as Geißberg. On the northern and western slopes, chestnut trees give the mountain a golden-tinged canopy in spring when seen from the Rhine plain. Near the Sprunghöhe saddle on the Gaiberger Weg, a large rhododendron planting dating from the 19th century blooms pink and white in late spring and draws many visitors.

The shortest ascent from the old town starts at the Stadtgarten and climbs steep serpentines to the Gaisbergturm, about 1.8 km. From the parking area at Gaiberger Weg near the Blockhütte, the summit is reached via the Sprunghöhe saddle in roughly 1.7 km round trip. The Riesenstein natural monument lies on the north slope along the Johannes-Hoops-Weg.

Near the summit stands the Gaisbergturm, whose viewing opening is kept clear by repeated cutting below it, allowing views west and north. Around the tower lies an arboretum laid out in 1876, whose sequoias planted then still stand in the Heidelberg city forest.