This map reflects the data from the Pew Research Global Religious Landscape. It reveals the two most common religions in each country, in proportion to each other. Please note that religions are obviously not evenly distributed across countries, but treating it this way is the simplest way to convey the basic information. Furthermore, this map does not show the fact that some countries have a far higher percentage of atheists and irreligious people than others.
Religion in North America
Christianity is the dominant religion in North America. It began to arrive in the 15th century, with the colonization of the continent by Spain, Great Britain, and France, among other European powers. Interestingly enough, according to the data set, the United States is the only country where Judaism is the second most common religion. However, it accounts for only 1.8% of the population. Some countries with a lot of people with African ancestry, like Cuba, Jamaica, and Haiti still have many people that follow traditional African folk religions.
Religion in South America
South America is another continent where Christianity is the dominant religion in all of its countries. The Spanish and Portuguese colonial empires actively sought to convert the indigenous peoples of South America to Christianity. Guyana and Suriname are the outlier countries on the continent. This is because many indentured servants from India were brought to these countries. As a result, Hinduism is followed by 25 percent of people in Guyana and 20 percent of people in Suriname.
Religion in Europe
Christianity and Islam are the two major religions practiced in Europe. No other religion in the region is one of the top two. Although Christianity originated in the Middle East, it spread to Europe via the Roman Empire. Albania and Kosovo are the only two countries that have a Muslim majority, although Bosnia & Herzegovina is nearly 50 percent Muslim, since they were once part of the Ottoman Empire. Outside of the Balkans, Western European has had steadily increasing Muslim population, in large part due to recent immigration.
Religion in Africa
Christianity and Islam are also the two major religions practiced in Africa, but there also some areas of the continent that still follow traditional African folk religions. In general, the northern regions tend to be more Muslim while the southern regions tend to be more Christian. Some countries, like Nigeria, Chad, Ivory Coast, Tanzania, and Ethiopia have nearly 50% Muslims and 50% Christians. Islam has a long history in Africa, since it was spread to the continent by Arab merchants. Christianity in Ethiopia and Eritrea has been practiced for more than a thousand years. More recently, Christianity has gained a lot of followers due to European colonization and subsequent missionaries to the continent.
Religion in Asia
Asia is easily the most religiously diverse continent. In at least one Asian country, the dominant religion is Christianity, Islam, Hinduism, Buddhism, and Judaism. Most people in the Philippines are Christian. Islam is dominant in many countries in West and Central Asia, as well as Bangladesh, Malaysia, and Indonesia. Hindus are concentrated in Nepal and India. Buddhism originated in India, but spread throughout Mainland Southeast Asia and East Asia. Many East Asian countries also practice their own traditional folk religions alongside Buddhism. Singapore is especially diverse. 34% are Buddhist, 18% are Christian, 14% are Muslim, and 5% are Hindu.
Religion in Oceania
Oceania is another region where Christianity is dominant due to European colonization and subsequent missionaries to the region. Fiji has the greatest amount of religious diversity in the region, since many decedents of indentured servants from India still follow Hinduism and Islam. Still, the country is 64% Christian. Australia and New Zealand also have a number of Hindus and Buddhists due to recent immigration from Asia.
High Resolution World Religions Map
A larger version of the map can be downloaded at the link below.