The Garner Marsh is one of the last remaining wetlands in Ancaster. It is a cold water system and supports a diverse community of species not found elsewhere in the area. It is part of the 13.7 sq. km subwatershed that feeds Ancaster Creek, whose name changes to Coldwater Creek when it merges with, among othe watercourses, Sulphur Creek, eventually running into Cootes Paradise.
The marsh has come under threat of development and/or misuse numerous times and it is covered in detail in this video by Save Our Streams Hamilton:
| Location | 79°58'3.194"W 43°11'56.098"N |
| Park | |
| Type | Wetland |
| Authority / Owner | Hamilton Conservation Authority |