Possil Marsh is a nature reserve and Site of Special Scientific Interest, of both flora and fauna, within the city of Glasgow, Scotland. The reserve was once part of an extensive system of lochs and marshes which extended throughout much of lowland West Central Scotland. However, centuries of drainage and reclamation have resulted in the elimination of much of this system. Due to its geographic position, the marsh is particularly vulnerable from industrial and residential development. The reserve contains a monument for the High Possil meteorite, which fell there in 1804.