| Değirmenburnu Nature Park | |
| Alt Name: | Değirmenburnu Tabiat Parkı |
| Map: | Istanbul |
| Label: | Değirmenburnu NP |
| Label Position: | top |
| Location: | Heybeliada, Adalar, Istanbul Province, Turkey |
| Nearest City: | Heybeliada |
| Coords: | 40.8839°N 29.0936°W |
| Area: | 12.28ha |
| Established: | 2011 |
| Governing Body: | Directorate-General of Nature Protection and National Parks Ministry of Environment and Forest |
Değirmenburnu Nature Park (Turkish: Değirmenburnu Tabiat Parkı) is a nature park in Istanbul Province, Turkey.
Değirmenburnu (literally "Cape Mill") is situated north of Heybeliada in Adalar district southeast of Istanbul Province. Heybeliada is the second biggest of the Princes' Islands, a group of nine islands in the Sea of Marmara. An area north of the island was declared a nature park by the Ministry of Environment and Forest in 2011. It covers an area of about 12.28ha.
In addition to outdoor activity of hiking and swimming, the nature park offers phaeton riding and bike rental on daily basis. There is an outdoor coffeehouse in the park.
Historic buildings such as the Heybeliada Sanatorium, the Eastern Orthodox Church Theological School of Halki and a mill are interesting sites in the park area to visit.
The island is accessible by passenger ferries from Kabataş at 20km (10miles), from Bostancı at 10km (10miles) and from Kartal at 6.5km (04miles) distance.
The area's climate is also effected by Mediterranean climate. Summers are hot and dry, winters are mild and rainy. The temperature difference between night and day is little. Dominnat wind direction is northwest. The winds are effective in the year around, and strong winds blow in the northwest direction in February and June. The lowest temperature observed in terms of seasonal temperatures is 4.3C in February, and the highest temperature being 31C in July. Relative humidity does not fall below 70% even in June or July.