| Site of Special Scientific Interest | |
 Devil's Gorge | |
  Location within Wales | |
| Location | Clwyd |
|---|---|
| Grid reference | SJ1800864866 |
| Coordinates | 53°10′28″N3°13′41″W / 53.174561°N 3.2281478°W |
| Interest | Biological and Geology |
| Area | 191.1 ha |
| Notification | 1 January 1957 |
Alyn Valley Woods and Alyn Gorge Caves is a Site of Special Scientific Interest [1] on the border of Flintshire and Denbighshire in north Wales. Most of the site is also designated as the Alyn Valley Woods Special Area of Conservation [2] and the southern part includes Loggerheads Country Park. The SSSI has an area of 190.3 hectares while the SAC covers 168.3 hectares. [1] [2]
A large part of the site is covered by broadleaved woodland with sessile oak, ash and sycamore among the dominant tree species. [1] Notable plants in the woods include stinking hellebore, green-flowered helleborine and wayfaring tree. [2] There are also areas of calcareous grassland with plants such as bloody cranesbill and lesser meadow-rue. [1] Much of the site lies on an escarpment of Carboniferous limestone and there are three cave systems: Ogof Hesp Alyn, Ogof Hen Ffynhonnau and Ogof Nadolig. [1] Lead ore, zinc ore, limestone and calcite were formerly mined in the area. [1]
