We assemble the Irish industrial data currently available for the years 1800-1921, the period during which the entire island was in a political Union with Great Britain, and construct an annual index of Irish industrial output for 1800-1913. We also construct a new industrial price index. Irish industrial output grew by an average of 1.3 per cent per annum between 1800 and the outbreak of the First World War. Industrial growth was slightly slower than previously thought, especially during the two decades immediately preceding the Famine. While Ireland did not experience absolute deindustrialization either before the Famine or afterwards, its industrial growth was disappointing when considered in a comparative perspective.