Algiers is the capital city of Algeria in North Africa. Algiers is located on a bay of the Mediterranean Sea and is an important port. Algiers was first settled over 1000 years ago and has now grown to a large city with a metropolitan population of over 3 million.lgiers is located on a bay of the Mediterranean Sea and is an important port. Algiers was first settled over 1000 years ago and has now grown to a large city with a metropolitan population of over 3 million.