The Great Famine was a period of mass starvation, disease and emigration in Ireland between 1845 and 1852.  During the famine Ireland&#x27;s population dropped by 20–25  percent, one million people died, and a million more emigrated from the island.  The proximate cause of the famine was a potato disease commonly known as potato blight.  The blight was so devastating because one third of the Irish population was entirely  dependent on the potato for food.