Although one religion may dominate a particular area other religions may also be practised there, as all six religions have spread throughout the world.
Christians are divided into groups (denominations.) The main Christian groups are Roman Catholics, Protestants and Orthodox Christians.
As this map shows one or other of these groups dominates North and South America, Europe and parts of Asia.
Most Christians are now located in the southern half of the world. Formerly most were located in the northern half.
Over the last century the percentage of the world’s Christian population based in Europe and North America has fallen by about 40%. This fall is expected to continue.
This is not due to people moving but simply because a growing number of people in Africa, Asia and South America are becoming Christians, whilst numbers in the northern half of the world are dropping.