The Jack Lynch Tunnel (Irish: Tollán Sheáin Uí Loingsigh) is an immersed tube tunnel and an integral part of the N40 southern ring road of Cork in Ireland. It is named after former Taoiseach, Jack Lynch, a native of Cork.It takes the road under the River Lee. North of the tunnel, the ring-road joins the M8 motorway to Dublin (north) and N8 road to the city centre (west), with the N25 commencing east to Waterford.