Rideau WatershedThe Rideau River flows through Eastern Ontario, Canada. From its beginning at Upper Rideau Lake the River flows north until the Ottawa River at Ottawa, Canada's capital. It passes through varied landscapes, which are at first forested and agricultural but become increasingly developed.

• Drainage Area: over 4,000 square kilometres of Eastern Ontario
• General Direction of Flow: Northerly
• Headwaters: Upper Rideau Lake near Newboro
• Confluence: At Rideau Falls it flows into the Ottawa River.
• Towns and Cities: 18 Municipalities including; Ottawa, Portland, Perth, Smiths Falls, Merrickville, Kemptville, and Manotick.
• Approximate Population: 620,000 people including a large part of the City of Ottawa.
• Total Length: The longest part of the watershed is about 180 km.
• Elevation: 204 m.
• Predominant Land Cover: Forestry (an estimated 40% of the watershed)
• Predominant Land Use: Agricultural, include dairy, beef and cash crop farming.
• Rivers and Tributaries: Rideau River, Kemptville Creek, Jock River, Tay River, Rideau Lakes.
  
• Original Settlement: Around 1790
• Other: At Newboro, an artificial canal was constructed by Colonel By in 1832 to connect the north flowing Rideau with the south flowing Cataraqui system to create the Rideau Canal. Its original purpose was defence against American attack but now serves as a major navigational and recreational boating waterway.