"Northern ones" refers to the Northern states in America during this time period. These include northern states such as New York, Massachusetts, Pennsylvania, etc.
Related terms
Textile industry: Refers to the production of cloth, especially through mass production using machinery in factories, which was a major industry in the Northern states during this period.
Immigration: The act of individuals moving from one country to another with the intention of settling permanently, as there was significant immigration to the Northern states during this time.
Canals and railroads: Infrastructure developments that played crucial roles in transporting goods and people across long distances within the Northern states.