Mass Effect: After Armageddon
Earth is the human homeworld. As the site of the Reaper War's final battle, Earth has suffered heavy damage from the reaper occupation. Its resources have also been stretched near to their breaking point due to the surge of displaced military and scientific forces left in the Sol System after the destruction of the mass relay network.
While many of these unwilling migrants returned home after the mass relays began to be repaired, some have remained and made Earth their new home.
Asari communities have sprung up in most large cities and near sites of historical human significance. One such outpost, New Stonehenge, has more asari residents than humans. Asari tourists have become common in every corner of the world.
Turians have primarily settled in warm climates, with large numbers in Mexico, Brazil, and India. Cultural differences have caused some conflict, as most of the native human populations do not take kindly to turian ideas of leadership.
Many Earth nations balked at the idea of krogan settlers, but the krogans found their home in one of the least hospitable environments on the planet: the Australian outback. Their settlement, Tuchankaustralia, is widely regarded as the wildest place on Earth.
While salarians have spread across the planet, mostly concentrating in cities and nations that keep science and industry well-funded, the de-facto center of salarian presence in the Sol System is Roswell, New Mexico. A site of historical significance to salarians, many of them refer to the now-booming metropolis as "our first home on Earth."
There are few quarian settlers on Earth, as most of them preferred to continue living with the Migrant Fleet with the hope that they could soon return to Rannoch. Similarly, other species did not settle on Earth in large numbers. The few drell have settled in arid climates, some hanar in the tropics, volus mostly in urban areas, and a handful of elcor have taken up farm work.