The valley lies to the south of Bangor. It is bordered one side by the Glyderau mountain range and on the other by the Carneddau. The River Ogwen (Afon Ogwen in Welsh) flows through it, separating the two mountain ranges. The valley is a part of Snowdonia National Park.
The Ogwen Valley, as a result of being bordered on all sides by mountainous regions, is home to many hill walkers, climbers, and campers. This level of recreational activity can at times result in people getting into trouble on the hills, and to address this problem the Ogwen Valley Mountain Rescue Organisation was set up. The work was initially started by Ron James at Ogwen Cottage outdoor pursuits centre; however, the need became great enough that mountain rescue in the area needed a full-time body to be initiated.
The northern parts of the valley include the small town of Bethesda, notable for the slate quarry, which was previously owned by Lord Douglas Penrhyn and giving the quarry its name, The Penrhyn quarry. It also includes also smaller villages such as Tregarth, Mynydd Llandygai and Rachub. Around 6500 people inhabit the valley as a whole, with around three-quarters of them able to speak Welsh.