International migration, also known as external migration, is the migration of people from another country into another. Immigration into a country adds to the total population of that country, while emigration subtracts from the total population of the country they are leaving. An example would be the waves of immigration to the Americas during the 18th and 19th centuries. Internal migration is the migration of people within that country's boarder. An example would be when African Americans began to move toward the North away from the South in the 19th century.
   The colonial period (17th and 18th centuries) of migration to America was mainly people from Europe, however this was also the time of slaves, so many Africans were also residing in America at this time as well as whites. The first wave of immigration (19th and early 20th centuries) was mainly again Europeans, and they settled along the East coast for the most part, railroads were established till mid 19th century, and the second wave of immigration included Europeans once again but from differents region, mainly south and east now, but during this time, America began to pass restrictions on immigration as laws. In the more recent times (late 20th century and 21th centuries) many Latin-American and Asian people have began to immgrate into the U.S.