The Irish represented the largest wave of immigrants, and they came first because of political and economic oppression in their homeland. They came, of course, in largest numbers in the wake of the potato blight and subsequent famine that began in 1845. Over 2 million Irish people entered the United States during the 1840s alone, and over 8 million arrived between the 1820s and 1880s. Their experiences were mixed. Many found jobs in the enormous infrastructure building projects of the 1820s and 30s, specifically canal digging. Many settled in cities and took manufacturing jobs, and others took service jobs meted out by political machines, like police officers and firefighters. After the Civil War, in which the Irish participated in enormous numbers, many recent immigrants went to work building railroads.