Kaštanka, Historic allée in Nasavrky, Czech Republic.

Kaštanka is a natural monument and park-like chestnut grove in Nasavrky, covering 1.08 hectares on a north-facing slope at 472–486 m. It holds 97 sweet chestnut trees of varied ages, surrounded by streets and buildings a few metres from the town square.

In 1776 Prince Auersperg brought six sweet chestnut seedlings from Italy and had them planted behind the Nasavrky chateau. Around a hundred trees were planted over time, of which twenty original specimens survive. The site was proposed for protection in 1986 and declared a natural monument on 1 December 1990.

The chestnut grove is called Kaštanka, and the oldest tree bears the name Knížák or Kněžák. The planting was started in 1776 by Prince Auersperg with six seedlings brought from Italy, and the site now serves as a public park with benches and a playground.

Kaštanka sits a few metres from Nasavrky's main square, ringed by a local road and town buildings, so it is reached on foot from the square. The 1.08-hectare orchard slopes gently to the north between 472 and 486 m; benches, children's climbing frames and a cinder volleyball court stand among the trees.

The oldest chestnut, called Knížák or Kněžák, has a trunk circumference of 534 cm, ranking it among the largest edible chestnuts in the Czech Republic. Of the roughly hundred trees planted over time, twenty original specimens survive, and the stand now numbers 97 trees of mixed ages, some over 200 years old.