87% of Riau's population was Muslim in June 2021.

Data from the Directorate General of Population and Civil Registration (Dukcapil) of the Ministry of Home Affairs recorded Riau's population at 6.45 million in June 2021. Of this number, 5.62 million people, or 87.11% of the province's population, are Muslim. This means the majority of the population in the province, known as Bumi Lancang Kuning, is Muslim.

The number of Christians in Riau is 624,060, or 9.67% of the population. The number of Buddhists in Bumi Lancang Kuning is 135,460, or 2.1%.

There are also 68,130 Catholics (1.06%), 2,200 followers of Confucianism (0.03%), and 761 Hindus (0.01%) in Riau. The number of people adhering to indigenous beliefs is 1,140 (0.0%).

Based on gender, 3.3 million (51.14%) of Riau's population are male. The remaining 3.15 million (48.86%) are female.

According to marital status, 3.03 million (46.87%) of Riau's population are married. 3.2 million (49.62%) are unmarried.

There are 57,150 (0.89%) divorced individuals and 169,160 (2.62%) widowed individuals in the province whose capital city is Pekanbaru.

Riau is a province in Sumatra with an area of 87,023 square kilometers (km) and a population density of 74 people per square kilometer. Administratively, Riau Province is divided into 10 regencies and 2 cities, comprising 169 districts, 1,591 villages, and 268 urban villages.