Froschfelsen, Natural rock formation in Ilsenburg, Germany.

Froschfelsen is a granite rock formation located on the western side of the Ilse valley near Ilsenburg. The stone sits at a higher elevation and offers views over the surrounding landscape from its position.

The rock gained its name from natural erosion that slowly shaped the granite into a form resembling a frog. This gradual weathering process has worked on the stone for thousands of years.

The name comes from the granite's resemblance to a sitting frog. The Froschfelsen is checkpoint No. 5 of the Harzer Wandernadel hiking badge system; the stamp box is kept in a refuge hut close to the rocks, so walkers collect it on their route.

The rock is accessible via several hiking trails in the area and sits in a region with good infrastructure for day visitors. Sturdy footwear is recommended since paths leading to the formation can be uneven in places.

The rock formation genuinely resembles a frog when viewed from certain angles, which often surprises visitors on closer inspection. This natural resemblance is what inspired the local name and makes it a popular spot for photographs.