Ma Shi Chau Special Area, Geological special area in Tai Po District, Hong Kong.

Ma Shi Chau Special Area is a protected zone in Tolo Harbour comprising four islands spanning 61 hectares of marine and geological formations. Trails run through the area, allowing visitors to explore the exposed rock layers and coastal features up close.

This area contains sedimentary rocks from the Permian period, approximately 280 million years ago, making it one of the oldest geological sites in Hong Kong. These ancient layers provide a window into the deep history of the region's formation.

The name Ma Shi Chau means "horse dung island", a reference to the dark, dung-like rocks found there. The area was designated Hong Kong's fourth special area on 9 April 1999. A nature trail lets visitors read the Permian and Jurassic rock layers, and the sandbar at Sam Mun Tsai is the only land link between Yim Tin Tsai and Ma Shi Chau.

Take minibus 20K from Tai Po Market to Sam Mun Tsai Stop, where you can cross a natural sandbank to reach the islands during low tide. Plan your visit around low tide times to walk safely and see the rock formations most clearly.

The sandbar linking Yim Tin Tsai to Ma Shi Chau is the only land route into the special area; the path from Sam Mun Tsai New Village is paved or stepped, and at both forks walkers must keep left, passing many graves along the way.