I would say that the potato famine in Ireland in the mid-1800's was rather than a pull phenomenon was a push phenomenon to push the affected people to seek a better life in this case in the US. Over 1 million Irish emigrated to the US at this time, some of them settling in Boston.
The potato famine in Ireland in the 1800's had a devastating effect on the Irish population. Two of the biggest consequences were:
1. Starvation; because of the potato famine around one million people had died from starvation which is close to 1/8 of the total Irish population in that period, and most of the population in the country was on verge of dying from starvation and barely made it through.
2. Migration; the potato famine caused a mass migration from Ireland towards the USA in order to have a better life or at least food on the table. It is estimated that probably around two million Irish people migrated to the USA in this period which is staggering almost 1/4 of the total Irish population.
