Lake Kainui, also known as Lake D, it is located within the Kainui peat bog which is in the Horsham Downs, Northern Hamilton. Lake Kainui is one among the series of the lake you can find in this area. It’s a shallow lake with a depth of 6.7 meters and an area of 27 hectares. The lake has significant ecological values and is highly influenced by peat which gives the water a unique tea-color (brown). The lake is managed by the Lake Kainui Land-care Group since 1966.

Lake Kainui is also a popular spot for recreational activities especially during summer. Around the lake, there is a well-maintained gravel trail which is suitable for hiking, running, and walking which was opened in the year 2018 for public. Apart from this they have maintained grass grown area too, that maintain the beauty of the place. You can do fishing and water skiing also in the lake. The lake Kainui is considered as the best lake for coarse fishery out of the eight small lakes found between Ngaruawahia and Hamilton.