Ffynnon Llugwy is a natural lake at an elevation of 554m (1,817ft) above the sea level, located in Caernarfonshire, in northern Wales. It’s one of the highest mountain roads of the country.
The road to the summit, in the Carneddau range of mountains in Snowdonia, is asphalted but pretty narrow. The road to the reservoir is owned by the power/water company and closed to cars. Starting from the A5road, the ascent is 2.54 km (1.58 mi) long. Over this distance, the elevation gain is 262 meters. The average percentage is 10.31 %. The maximum gradient is 15.0%.