While long-term records that extend into the nineteenth century exist for various meteorological variables, river flow records of concurrent length do not exist on the island of Ireland. This work attempts to reconstruct monthly river flows for twelve Irish catchments using quality assured long-term precipitation records for the period 1850–2015. A conceptual rainfall-runoff model calibrated and verified on contemporary flow records is used to reconstruct monthly flows for each catchment. Reconstructions are then analysed to identify periods of drought using a threshold-based drought indicator. Results show that the catchments examined experienced protracted drought episodes with seven major drought rich periods identified in 1887–88, 1891–94, 1902–12, 1933–34, 1944, 1953, 1971–76. The timing and severity of hydrological droughts are consistent with previous work that has examined meteorological drought. This work thus provides a first attempt to reconstruct historical river flows to examine hydrological drought in Ireland. We tease out directions for future work and the opportunities presented for using such reconstructions for drought risk management.