St Eunan's Cathedral, properly the Cathedral of St Eunan and St Columba, was built between 1890 and 1900 and opened in 1901 on a site overlooking the town. It is Victorian neo-Gothic by William Hague, a protégé of Pugin, and its spire rises 73 metres. It is the only Catholic cathedral in County Donegal.
Inside, the oak furnishings, the marble pulpit with the Four Masters and the Four Evangelists, the Munich stained glass and the painted ceilings by Amici of Rome are all worth a look; some of the sculptures are by Willie Pearse, who took part in the 1916 Easter Rising. The cathedral is open daily. Across Cathedral Square, the older Conwal Parish Church (Church of Ireland) dates from the 17th century.