The largest regency by land in Papua province, It covers an area of 23,813.91 km2, but had a population of only 18,365 at the 2010 Census[2] which had almost doubled to 36,483 at the 2020 Census;[3] the official estimate as at mid 2023 was 38,636 (comprising 20,171 males and 18,465 females).

The Yapen Islands Regency in the Cenderawasih Bay lies to the northwest.

The highest elevation in this regency is near the summit of the Gauttier Mountain Range, at ~2,200 m above sea level; the actual summit of the Gauttier Mountains lies in Sarmi Regency.

Languages spoken in Mamberamo Raya Regency:[4] At the 2010 Census the regency comprised eight districts (distrik), tabulated below with their areas and their populations at the 2010 Census[2] and the 2020 Census,[3] together with the official estimates as at mid 2022.

[5] The table also includes the locations of the district administrative centres, the number of administrative villages (kampung) in each district, and its post code.