The village is located at the southern end of the Maam Valley, where it comes to Lough Corrib; the other end lies at Leenaun on Killary Harbour. The settlement lies at an altitude of around 20 metres, between where the main river of the southern two thirds of the valley, Joyce's River, is captured by the larger Abhainn Beal Atha na mBreac (Bealnabrack River) and where the Failmore River joins that river's mouth at the northern end of the lake. It sits at the edge of a mountainous area, the principal part of which forms the Maumturk or Maamturk Mountains.

An Mam lies north of Maam Cross, an important crossroads from which the main road serving the settlement, and providing a secondary route through the Maam Valley to Leenaun, the R336, comes, splitting off from the R59 Galway to Clifden road. Maam Bridge, built in 1823, takes the R336 across the Bealnabrack River.