Before the civil war which region had the larger urban population by 1860

It’s North

While the Northern states needed immigrants, freemen, to create and work in the tens of thousands of small farms as well as the city and town jobs (factories that employed a thousand or more workers were far more common then and many towns had factories with several hundred employees) so while there was substantial anti-immigrant politicking by the nativist movement, in general far more newcomers came in to the North.