Edwardsburgh/Cardinal is a township in the United Counties of Leeds and Grenville of eastern Ontario, Canada. Edwardsburgh township was first surveyed in 1783, and incorporated in 1850. The township was formerly a part of the historical Grenville County before it merged with Leeds County to form the United Counties in the 19th century.The Township of Edwardsburgh/Cardinal was formed on January 1, 2001, through the amalgamation of Edwardsburgh Township with the Village of Cardinal.It is a historical community with many old homes and buildings; including one-room school houses, grist mills, and churches. It is situated along the St. Lawrence River Seaway and extends back into rural hamlets. Both Highway 416 and Highway 401 pass through the township, as well as the South Nation River.The township's main population centres are Cardinal, Johnstown, and Spencerville.GeographyEdwardsburgh/Cardinal's southern boundary is the St. Lawrence River's shore. To the west, the township ends at the boundary for Augusta Township and to the east is the neighbouring county of Stormont, Dundas and Glengarry. To the north of the township is the township of North Grenville. The township covers an area of 312 km2. The township belongs to the Great Lakes–St. Lawrence lowlands region.Despite the township's proximity to the St. Lawrence River, only ten percent of the area's water drains into the St. Lawrence, and ninety percent drains into the South Nation River. The flow of the South Nation river through this area is described as very sluggish with poor drainage, due to the fact there is little drop in elevation along the river; this leads to the formation of bogs and swamps, and also makes the area prone to seasonal flooding. The north-west section of the township is known as the Groveton Bog, and to the east is known as the Hellgate Swamp. The soils in the area range from sandy and dry, to dark and acidic closer to the swamp areas.