Karatu District in the context of Districts of Tanzania

The Iraqw people (/ɪˈrɑːkuː/) are a Cushitic ethnic group inhabiting the northern Tanzanian regions. They dwell in southwestern Arusha and Manyara regions of Tanzania, near the Rift Valley. The Iraqw people then settled in the southeast of Ngorongoro Crater in northern Karatu District, Arusha Region, where the majority of them still reside. In the Manyara region, the Iraqw are a major ethnic group, specifically in Mbulu District, Babati District and Hanang District.

The Datooga (Wamang'ati in Maasai language meaning enemy, a name adopted into swahili) are a Nilotic ethnic people group from Tanzania that are closely related to the Kalenjin ethnicity in Kenya and Uganda, located in Karatu District of Arusha Region and historically in areas of southwest Manyara Region and northern Singida Region. In 2000, the Datooga population was estimated to number 87,978.

The Hadza, or Hadzabe (Wahadzabe, in Swahili), are a protected hunter-gatherer Tanzanian indigenous ethnic group, primarily based in Baray, an administrative ward within Karatu District in southwest Arusha Region. They live around the Lake Eyasi basin in the central Rift Valley and in the neighboring Serengeti Plateau. As descendants of Tanzania's aboriginal, pre-Bantu expansion hunter-gatherer population, they have probably occupied their current territory for thousands of years with relatively little modification to their basic way of life until the last century. They have no known close genetic relatives and their language is considered an isolate.

Since the first European contact in the late 19th century, governments and missionaries have made many attempts to settle the Hadza by introducing farming and Christianity. These efforts have largely failed, and many Hadza still pursue a life similar to their ancestors. Since the 18th century, the Hadza have come into increasing contact with pastoralist peoples entering Hadzaland, sometimes declining in population. Tourism and safari hunting have also affected them in recent years.

Ngorongoro District (Wilaya ya Ngorongoro, in Swahili) is one of seven districts in western Arusha Region of Tanzania. The district is bordered to the north by Kenya, to the east by Monduli District, the northeast by Longido District, and to the south by the Karatu District. The western border is the Serengeti District in Mara Region. Ngorongoro District is home to the Ngorongoro Crater and was named after it. It covers an area of 14,036 km (5,419 sq mi). The district is comparable in size to the land area of Timor Leste. The administrative seat is the town of Loliondo. The district is home to the Ngorongoro Conservation Area which is a UNESCO World Heritage Site. The district is also home to the third tallest mountain in the country, Mount Loolmalasin. According to the 2002 Tanzania National Census, the population of the Ngorongoro Region was 129,776. By 2012, the population of the district was 174,278. By 2022, the population had grown to 273,549.

Lake Eyasi (Swahili: Ziwa Eyasi; formerly German: Njarasasee, "Njarasa Lake", and Hohenlohesee, "Hohenlohe Lake") is a lake located in Karatu District of Arusha Region in north Tanzania. Lake Eyasi is the largest body of water in Arusha region. It is a seasonal shallow endorheic salt lake on the floor of the Great Rift Valley at the base of the Serengeti Plateau, just south of the Serengeti National Park and immediately southwest of the Ngorongoro Crater in the Crater Highlands of Tanzania. The lake is elongated, orientated southwest to northeast, and lies in the Eyasi-Wembere branch of the Great Rift Valley.

The principal inflow is the Sibiti River, which enters the southwestern end. The river may continue to flow somewhat year round, at least in wetter years; the other inflows are all seasonal. The second largest inflow is the Baray, at the northeast. The water carried by the Baray has increased in recent years due to deforestation of the Crater Highlands. The southwest flank of Mount Oldeani, one of the Ngorongoro volcanos, drains directly into the northeast end of the lake. Flow from the Budahaya / Udahaya River, which drains into the Yaeda Swamp to the southeast of the lake, was once second, but has decreased due to water diversion in the Mbulu Highlands. Water flow from the Serengeti is minor; the largest stream is the Sayu.