Chaldeans are a Semitic people from Northern Iraq and Southern Turkey, related to the Assyrians of the same area. Historically they centered around the village of Tel Keppe (or Tal Kayf), located near Mosul, Iraq. They predate the Islamic opening, being descended from the original inhabitants of Mesopotamia. They speak a language known as Chaldean Neo-Aramaic, which is rooted in ancient Aramaic and has an alphabet close to that of Hebrew and Arabic. Some 120,000 people speak this language in Iraq, with another 70,000 speakers living in the United States. Chaldeans are Christian, with the majority belonging to the Chaldean Catholic Church, and were one of the first peoples to be converted to that religion by St. Thomas in 33 A.D. All belonged to the Eastern Orthodox Church until 1552, when missionaries from Rome reunited their rite with the Pope. Those who remained with the Orthodox church have referred to themselves as Assyrian since the split.

The total population of Chaldeans is estimated at 1 million world-wide. There are today some 250,000 living in the United States, with 150,000 Chaldeans and the remainder belonging the Assyrian Church. Major populations of Chaldeans are found around Detroit, MI and San Diego, CA - while Assyrians are concentrated around Chicago, IL. Elsewhere in the world, an estimated 100,000 Chaldeans live around Baghdad, Iraq. Around 3,000 remain in Tel Keppe.