Emigrants from Portugal began arriving in the United States in the middle of the 19th century. Early arrivals settled in Boston, Cambridge, Lowell and New Bedford. Fishing and working in the cotton mills were the chief forms of employment. In Illinois there were two settlements of Springfield and Jacksonville.

Numbers increased significantly after 1890. The main reason for this was high taxes, low wages and the problems of tenant farming. Large numbers worked in the textile mills of New Bedford that paid wages ten times those available in Portugal.

From 1899 to 1919 the total Portuguese immigration to the United States was 143,653. After the First World War emigration from Portugal virtually came to an end.

An investigation carried out in 1978 revealled that since 1820 over 446,000 people emigrated to the United States from Portugal. This amounted to 0.9 per cent of the total foreign immigration during this period.