West of Borrisokane the Ballyfinboy slips past Ballyfinboy Castle, a ruined tower house with a Sheela na gig carved into a panel on its western wall. That carving – a medieval female figure of the kind found on a scatter of Irish church and castle walls – is the most distinctive thing on the river, and the castle it sits on stands on a 2.5-acre plot about a 12-minute drive from Nenagh.
The river itself rises near Moneygall in County Offaly and runs generally northwest for about 33km, through Cloughjordan and Borrisokane, before emptying into Lough Derg at Drominagh. For much of that course it forms part of the boundary between Offaly and Tipperary, draining a catchment of roughly 193 square kilometres into the Shannon system.
The bridges
The crossings are the real interest here. The pick is the three-arched Drominagh Demesne toll bridge near the mouth of the river, built in 1776; the disused toll collector’s shelter is still in the parapet, and the booth on the west side carries a plaque reading ‘This Bridge was Built 1776. Richard Biggs Esqr Overseer’. Upstream, Knockearl Bridge carries the R491 from the Offaly bank across to Cloughjordan in Tipperary, and Ballinderry Bridge takes the R493 over the water on five low arches. There is also an ornate stone bridge with cast-iron railings on the avenue to Modreeny.
Fishing and access
The Ballyfinboy is a recognised salmon and trout river. An Inland Fisheries Ireland electric-fishing survey at Ballinderry in September 2012 turned up 26 brown trout and 15 salmon, which gives a fair sense of the stock. If you want to fish it you need a valid Inland Fisheries Ireland licence and should follow catch-and-release guidance.
Be realistic about what this is: a quiet rural river, not a developed visitor site. There is no waymarked riverside loop, and most of the bank is farmland reached from the road bridges. The one easy, car-free stretch of riverbank is Borrisokane Town Park, which sits on both sides of the river and was created and paid for by the townspeople rather than the council, with modern footbridges linking the two halves. Start there.
The valley runs along the R491 and R493, with Borrisokane and Cloughjordan both on the route and parking in each. Buses connect Nenagh and Birr to the surrounding villages, and the M7/M8 and M6/M18 bring you in from Dublin and Galway. Birr Castle, with its gardens and the Great Telescope, is the obvious half-day add-on; Lough Derg, where the river ends, is the place for boating and a shoreline drive.