Dellenhäule, Nature reserve in Aalen and Neresheim, Germany.

Dellenhäule is a nature reserve located between Aalen and Neresheim with rolling meadows and scattered oak woodlands. The area includes both open grasslands and forested sections linked by walking paths.

The area received official protection in 1969 due to its ecological value for wildlife and plants. The landscape today reflects centuries of farming and land management practices.

Sheep herds still graze here today, and visitors can watch this traditional practice shape the open meadows during their walks. This continuous method of land care supports the survival of rare plant species.

The reserve lies about 1,000 metres south of Beuren, a hamlet in the Waldhausen district of Aalen. It is enclosed by the larger Kugeltal, Ebnater Tal and Heiligental landscape protection area, and paths cross juniper heath and open pasture. Keep to the trails, since the ant mounds on the former field are easily crushed underfoot.

On a former field of just under 2 hectares, yellow meadow ants have nested for about 130 years, with up to 14,000 mounds at peak times. Biologist Bernhard Seifert of the Senckenberg Museum in Görlitz counts this "ant city" among the world's largest occurrences of a single ant species. Green woodpeckers and wrynecks feed here.