The Ethnologue describes the location of the Ngongo people as follows: Bandundu Province of the Democratic Republic of Congo (DRC). However, there is an Ngongo group that is a sub-group of the Nkutu, which is a larger group, and their location is in Northern Kasaï Oriental Province of DRC.
There is another group called Ngongo among a neighbouring language group, the Bushoong. Total Bushoong language speakers number about 155,000, according to the Ethnologue. The number of Ngongo who speak The Bushoong language (buf) is not known. The Bushoong are neighbours of the Nkutu group, across the border of Kasaï Occidental Province, Mweka and north Ilebo territories.
The Ethnologue provides a map that shows where each of the language groups is thought to be. This gives us a picture of the geographical relationship of these groups.
Sources report that they live in the forest, where they clear out small areas for their basic living. Access is very difficult, with few roads in this region of DRC. The identity of the Ngongo cluster of peoples is strongly tied up with the languages they speak. See more discussion in the Language section below. PeopleGroups.org reports a population of 185,078 for the Ngongo. They report this group, however, under the ROP code 107281, corresponding to the Ngongo people.
Other sources, however, report the Ngongo as having a population of only about 5000. This is the number of speakers reported by Ethnologue for the Ngongo language (noq). Ethnologue Edition 16 reports that most of the Ngongo speak Kituba (ntu). There is not a separate population given in CPPI or other sources for the Ngongo sub-group of Nkutu.
People Groups.org reports the Ngongo entity with the Nkutu language (nkw), not the Ngongo language. They also lists the Nkutu people separately with their language, also with a large population (119,406). But they do not report any Ngongo group with the expected lower population and the Ngongo language (noq).
The main body of the Ngongo is to the northwest of the Nkutu people, so it is easy to envision that the Ngongo were a larger people who were surrounded by others or groups of Ngongo migrated a small distance away and began to relate to other language and ethnic streams.
The smaller Ngongo-speaking body and the Ngongo groups speaking other mother tongues may still relate to one another. This needs to be explored by personal investigation on site. There are many cases in Africa of multi-lingual ethnicities who still consider themselves related and maintain some affiliation. Further field investigation is needed to clarify this aspect of the peoples called Ngongo.
This proximity of the locations where the different Ngongo groups are now found, with a group called Ngongo who speak a form of each of these two major languages (Bushoong buf and Nkutu nkw) supports a historical picture of a dispersion and possible pattern of assimilation of an original people called Ngongo speaking their own language, now represented in the smaller Ngongo group speaking Ngongo (language code noq).
All these Ngongo groups are thus probably derived from the same broad, original Ngongo people, and these two groups have moved into the other language stream.
There are three possibilities here:
1. CPPI has included the Ngongo segment who speak Nkutu language to get the higher population for the Ngongo entry (with the larger group's language and no Ngongo language). In this case, however, it is not clear that the population for the Nkutu speakers has been adjusted to account for the deduction of the Ngongo dialect of Nkutu.
2. CPPI has confused the Ngongo people (ROP 107281, ROL noq) with the speakers of Ngongo dialect of Nkutu people (ROP 107363, nkw, Ngongo dialect), or
3. CPPI editors have determined that the Ngongo ethnic group (107281) with its own language by the same name (noq) is actually now extinct, or no longer speaks a distinctive language, and have used the Ngongo name to represent the Ngongo segment of the Nkutu people. Populations are uncertain or old in most sources, so the population is not a viable cross-check to clarify the situation.
The discussion above includes some of the information on language that is involved with the identification of an ethnic group by the name Ngongo. The name Ngongo refers to a dialect of the Bantu language Nkutu, uniquely identified by the language code nkw and dialect name Ngongo. (The Registry of Peoples earlier editions used an unofficial dialect code NKW05 for this Ngongo dialect, which is also used by some databases.)
The name Ngongo also refers to a unique ethnic group with their own language also called Ngongo, uniquely identified by the language code noq. This is a small group whose language is called Ngongo (noq), with a population of about 5000. This Ethnologue figure is the number of speakers for the Ngongo language, not necessarily the ethnic population.
The language of this people is in the Yaka group, which are related to the widely-spoken Kongo and Mbundu languages. It is not related to the Nkutu language. This Ngongo ethnic group are also, according to the Ethnologue, "quite bilingual in Kituba" (ktu), a Creole of Kongo language used by various tribes as an inter-language.
The speakers of Nkutu are the descendants of the ancient Mongo empire. The Mongo are now represented by a large group of tribes with different languages. There are several other languages, also, that have a dialect called Ngongo. It is unclear if any of these Ngongo sub-groups might be counted together by some sources as a separate Ngongo entity with a larger population.
The Ethnologue reports the religion of the Nkutu as Traditional Religion, while it had no information the religion of the Ngongo people. The Ethnologue reports that the Bushoong people are some traditional and some Christians, without specific statistics. No further details are available about the Ngongo sub-group of the Bushoong speakers.