Gaerwen is a village on the island of Anglesey in the community of Llanfihangel Ysgeifiog. It is located in the south of the island 4 miles (6.4 km) west of Llanfairpwllgwyngyll and 4 miles (6.4 km) southeast of Llangefni. The A5 runs through the village, and the A55 runs just a few hundred metres north. According to the 2011 Census Gaerwen is now listed by the Office for National Statistics as Llanfihangel Ysgeifiog. The population of the community is 1,551. Gaerwen and Pentre Berw, Llangaffo are trio villages.