The majority of Penajam Paser Utara's population was Muslim in June 2021.

Penajam Paser Utara is one of the regencies in East Kalimantan that is a candidate for the Nusantara Capital City (IKN). The Directorate General of Population and Civil Registration (Dukcapil) of the Ministry of Home Affairs reports that the majority of the population of Penajam Paser Utara is Muslim.

The population of Penajam Paser Utara Regency was 185,000 in June 2021. Of this number, 175,552 people (94.88%) are Muslim.

There are also 6,891 people (3.72%) who adhere to Christianity, and 2,451 people (1.32%) who are Catholic.

There are also 86 people (0.05%) who adhere to Hinduism, 41 people (0.02%) who are Buddhist. There is also 1 person registered as adhering to an indigenous belief system.

The IKN is located in a National Strategic Area (KSN) covering 256,142 hectares, situated in two regencies: Penajam Paser Utara and Kutai Kartanegara.

Penajam Paser Utara Regency has an area of 3,333.06 square kilometers with a population density of 56 people per square kilometer. Administratively, it is divided into four sub-districts: Penajam (1,163.62 square kilometers), Waru (569.42 square kilometers), Balulu (388.91 square kilometers), and Sepaku (1,129.48 square kilometers).