While there are many, many Christian denominations in the United States of America, the USA is not the only nation that has Christians, and there are many denominations in other countries, as well. In most cases, the ones below are the predominant Christian community in the area in which they live and worship.
The term Christian refers to those who believe in the God of the Bible and follows the tenets set forth therein.
Armenians (Western Asia)
Located primarily in the Armenian Highlands in Western Asia, the Armenians follow the Armenian Apostolic Church, which is the world’s oldest national church. Following the church-planting activities of two of Jesus apostles – Thaddeus and Bartholomew – Christianity was adopted as the state religion of the Kingdom of Armenia in the early 4th century.
The Coptic Christians are the largest Christian denomination in the Middle East and North Africa. There are also some Copts in Libya and Sudan, where they are the largest Christian communities in those respective countries.
The largest portion of Copts follow the Coptic Orthodox faith, which is part of the Oriental Orthodox church, while the remainder are in communion with the Eastern Catholic church.
Greek Christians (Greece, Middle East, Europe)
Primarily located around Syria and Lebanon, the Antiochian Greek Christians are either part of the Greek Orthodox Church or the Melkite Greek Catholic Church. Rooted in Syria and its surrounds, these Arabic-speaking Christians use Koine Greek in their liturgy, which is the basis for the name.
Jews (Worldwide, Israel)
While most Jews do not identify as Christians, they worship the God the Christians worship and use the same sacred book, so it is reasonable to include them in a collection of Christian denominations. Originating in the Middle East, the Israelites (or Hebrews) have spread throughout the world, but have, in the last century, again begun inhabiting primarily the land in the Middle East that was historically theirs. There are still large populations around the world, including the United States, France, Canada, Mexico, and many more countries.
Judaism follows primarily the Old Testament of the Bible, as most do not recognize Jesus Christ as the foretold Messiah. They still look forward to a coming Messiah. Their worship is liturgical and follows the information set forth in the Torah.
Karaites / Krymkaraylar (Northern Asia)
Known as the Crimean Karaites, Krymkaraylar, Karaims, or Qarays, this group speaks Turkish and follows a form of Judaism. They are mostly located in Central and Eastern Europe, especially in the area of the former Russian Empire. Their holidays are mostly the same as Judaism’s, and they revered both Jesus and Mohammed as prophets.
Karaite Judaism was the only religion observed by the Karaim until the 20th century.
The Karaite community in Berlin was not considered Jews during the Holocaust, after that legal status was determined by the Reich Agency for the Investigation of Families, even though much of their worship and beliefs were related.
Russian Orthodox (Russia)
Russian Orthodox is the self-proclaimed faith of over half of the entire Russian population. Even Russians who are not religious may choose to associate themselves with the church because it fits their culture; however, practicing Russian Orthodox Christians form a large portion of the population.
One thing Russian Christians are known for are the icons they have painted, which come in many types and styles. These may be painted on walls, but more often are on pieces of wood or made of copper. These are done carefully, as they are considered to be the gospel in paint which must be conveyed accurately. They were considered miraculous and have sometimes been said to “appear.”
Based on the Pentateuch (also known as the Torah), the Samaritans follow a religion very similar to Judaism. They believe the faith they follow is the one the Israelites followed before the Babylonian captivity, and that Judaism has been changed because of the captivity. Their liturgy uses both Hebrew and Arabic.
Serbian Orthodox (Serbia)
The Serbian Orthodox Church was established in the 11th century and is led by the Serbian Patriarch. There are around 10 million people who follow this faith. It is the largest group of any religion in Serbia and Montenegro, and comes in second for that designation in Croatia, Herzegovina, and Bosnia. Some adherents also have spread to North Macedonia, North America, Australia, and Western Europe.
Syriac Christians (Middle East)
The Assyrian people, indigenous to Western Asia (Middle East), are also known as Syriacs. The original Assyria dates back to 2500 BC and is one of the oldest civilizations in the world. These Syriacs, of whom some call themselves Arameans or Chaldeans, are likely descended from this civilization, and many still speak Aramaic.
The doctrine followed by these Christians is the West Syrian Rite Syriac Orthodox Church. While most of the Syriac Christians live in the areas of Syria, Iraq, and Turkey, there are groups that have moved to Israel, Germany, Sweden, and the United States.
This group also includes the Maronites (Lebanon) which follow the Syriac church, in the Lebanon area. It is an Eastern Catholic church that recognizes the Pope but has self-governance. They took their name from a Syriac Christian saint called Maron. They do have some adherents that have spread into Syria, Israel, Palestine, and Cyprus, and some Lebanese in other areas also follow this faith.
Also known as Waldenses, Vallenses, Valdesi, or Vaudois, this group was founded in the 10th century by Peter Waldo. Their doctrine is Reformed, and generally relates to Methodist, as many congregations are a union between Waldensian and Methodist. While they are primarily in Italy, there are active groups in Europe, South America, and North America.
Christians come in many countries, ethnicities, and formats. It can be interesting to compare and contrast what you believe with Christians who have different backgrounds and culture. The main thing that all Christians have in common, though, is that all Christians believe in a God who created all things and is worthy to be worshipped by His followers, regardless if the form of worship is the same from group to group.