The River Nanny is a small river in County Meath that flows through Duleek and the Duleek hinterland in east Meath before entering the Irish Sea at Laytown. The river meanders through agricultural land and is described as shallow and bubbling in its upper reaches, with an expansive tidal estuary near its mouth where it meets the sea at Laytown beach.

The primary paddling activity on the river is paddleboarding, with guided tours operating from Laytown along what is described as the River Nanny route. Four Shore Adventures, based in Laytown, runs guided paddleboard tours of approximately two hours in duration, as well as shorter sunrise and sunset experiences of around 1.5 hours. Tours are offered daily, subject to weather conditions, and cater to all ability levels from complete beginners to experienced paddlers. The River Nanny Car Park at Laytown (coordinates 53.678448, -6.240908) serves as a practical access point, located near the train station which also provides a large car park, though it can become busy.

The estuary near the river mouth is a notable wildlife area, attracting gulls and waders at low tide, including Black-tailed Godwit, Common Gull, and Stonechat. Sand dunes in the area support buntings and chats. A path running under the railway bridge follows the estuary and leads out to the beach, offering views of the tidal flats. The iconic Nanny Water Cottage, an 18th-century stone thatched structure originally built as a coastguard station, sits at the point where the river meets the sea and is a notable landmark on the water.

The river carries some local folklore, including a legend that St. Patrick cursed the Nanny so that no salmon would ever be caught in its waters. The river does hold stocks of wild brown trout and sea trout, with the fishing season running from February to September, which may be relevant context for paddlers sharing the water with anglers during those months.