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 valley was historically dependent on the roofing slate industry and it suffered from its decline from the 1960s onward. The only other significant source of employment was and still is mountain sheep farming. Unemployment is currently around 20%.
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.
Clwb Rygbi Bethesda (Bethesda Rugby Club) is the focus of social life in the valley and all boys play rugby from a young age.
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. At its peak in the early 20th century, over 20,000 people lived in the valley, but this has now declined to around 6500. Three-quarters of inhabitants are able to speak Welsh. According to the Welsh Index of Multiple Deprivation, all wards in the valley are amongst the poorest 10% in Wales, with one ward among the poorest 3%.
Its inhabitants are traditionally mocked as "Howgets" because of their lack of education and inability to speak English. Ysgol Dyffryn Ogwen is the secondary school for the entire valley.