Immigrate vs. Emigrate vs. Migrate

Emigrate - to leave your country permanently in order to settle in another.

- In the event of drought and starvation in Africa, many people emigrated to the European
countries.

From...to
He emigrated from Morocco to France to find work.

Immigrate - Enter a new country and change residency permanently.

- My parents immigrated to the United States in 1960.

From...to

Migrate
1- (of animals)to leave your location periodically or seasonally.

- The birds migrate south in the winter .

2- (of people) to travel in large numbers to a new place temporarily in order to find food,work,...

- Farmers have learned that they have to migrate if they want to survive.
- Mexican farm workers migrate into the US each year to find work at harvest time.

There are two differences between the emigrate and immigrate:

When you want to focus on leaving a country/region, you need to use emigrate.For example in this sentence: His brother had emigrated from Germany when he was 9.

Speaker means his brother left Germany.

If you mean someone moved to somewhere, you should use immigrate:

- His brother had immigrated to the U.S when he was 9. speaker wants to say that he moved to the U.S....

Another difference between emigrate and immigrate is that the former is transitive while the latter is both transitive and intransitive .

- The president ordered to immigrate some of the tribes in this part of the country to the
southeast parts.

References:
American Heritage dictionary
Cambridge Advenced Learners' Dictionary
Longman Advanced American Dictionary
Collins Cobuild-Lexicon dictionary