The Dublin to Sligo main line is a railway route operated by Iarnród Éireann in Ireland. It starts in Dublin Connolly station, terminating at Sligo Mac Diarmada railway station in Sligo. The route is a double-track railway as far as Maynooth, being a single-track railway with passing loops between there and Sligo.

Connolly station or Dublin Connolly is one of the busiest railway stations in Dublin and Ireland, and is a focal point in the Irish route network. On the North side of the River Liffey, it provides InterCity, Enterprise and commuter services to the north, north-west, south-east and south-west. The north–south Dublin Area Rapid Transit (DART) and Luas red line light rail services also pass through the station. The station offices are the headquarters of Irish Rail, Iarnród Éireann. Opened in 1844 as Dublin Station, the ornate facade has a distinctive Italianate tower at its centre.