Merrickville is a small village on the Rideau Canal, close enough to Ottawa for an easy day out but far enough away to feel like a separate little world. Its best asset is not one single sight, but the way the canal, stone houses, old mills, and craft shops sit together in a compact, walkable centre.
Start at the Merrickville Lockstation, where boats still move through the Rideau system, then cross to the Blockhouse Museum. The blockhouse gives the pretty village a harder military edge: this canal was built for defence as much as transport.
Merrickville is best on foot. Wander St. Lawrence Street and Mill Street, look into the small shops and studios, and leave time for the Industrial Heritage Complex, which explains why this was more than a scenic canal stop. It is not a big place, but it has enough texture for a very good half-day.