Based on the population distribution shown in the table and the context of migration trends, the correct evaluation of the cause of increased migration to the U.S. is:
There was overseas migration from Europe and Asia to U.S. port towns.
This statement is supported by the data showing an increase in urban population, which is typically associated with migration. During the time periods reflected in the table, there was a significant influx of immigrants arriving in port towns, leading to urban growth. The other options do not accurately describe the trends reflected in the table.