The Jamison Valley stretches north-south from just outside of Katoomba to Coxs River; in this direction it is approximately 12 kilometres (7.5 mi) long. From west to east, it stretches from Narrow Neck Plateau to Kings Tableland, making it approximately 10 kilometres (6.2 mi) wide.
Like the entire Sydney and Blue Mountains region, the valley is a sandstone area, characterised by steep sandstone cliffs. Deeper into the soil there is a layer of shale, which is softer than the sandstone. As this layer of shale was eroded by the watercourses, it collapsed and brought the sandstone down with it, creating the characteristic sandstone valleys and canyons of the Blue Mountains, of which the Jamison Valley is one.
The valley is densely forested, with eucalypt forest over most of its expanse and occasional pockets of semi-rainforest in gullies, where water is concentrated. The northern escarpment is deeply serrated, having been carved up by watercourses over millions of years. Watercourses include Jamison Creek, Valley of the Waters Creek, Gordons Creek, Leura Falls Creek, Kedumba River and Causeway Creek. There are also numerous waterfalls, including Wentworth Falls, Empress Falls, Vera Falls, Gordon Falls, Leura Falls and Katoomba Falls.