Crater Lake sits inside a small game sanctuary on the western side of Lake Naivasha. The crater itself — a near-perfect circular lake — is the collapsed caldera of an old volcano, its walls forested and steep. The sanctuary around it protects a small population of black-and-white colobus monkeys, as well as giraffe, impala, and waterbuck.
You can walk the trail around the crater rim on foot. The main crater lake is vividly coloured — alkaline rather than fresh — and birdwatching in the forest around it is excellent. It is one of the quieter spots in the Naivasha area, often bypassed by visitors heading straight for the main lakeshore.