Brosna, County Offaly  Brosna () is a small village in County Offaly, Ireland. It lies in the valley of the Little Brosna River less than one kilometer off the N62 national secondary road. Farms and a plumbing business operate in the area. Brosna House, an early 19th-century two-storey house located at the roadside, is listed as being of architectural interest. A late 19th-century cast iron water pump also stands in the village.