Nunukan Regency

Nunukan Regency is a regency of North Kalimantan Province in Indonesia. It was created on 4 October 1999 from the northern districts of Bulungan Regency. Nunukan Regency shares international borders with the Malaysian states of Sabah to the north and Sarawak to the west, and inter-regency borders with Tana Tidung Regency and Malinau Regency to the south, as well as the coastal city of Tarakan in the east. The regency covers an area of 14,247.50 km² and it had a population of 140,841 at the 2010 census and 199,090 at the 2020 census; the official estimate as at mid 2024 was 227,460 (comprising 119,672 males and 107,788 females).

Nunukan is also the name of an island within this regency. It has an area of 226 km². Nunukan town, the capital of the regency, is located on Nunukan Island, which comprises the insular section of Nunukan District (which also includes part of the 'mainland' of Kalimantan) and the whole of the separate Nunukan Selatan District. It is a major port for ferry crossings to Tawau in Sabah state, Malaysia.

North of Nunukan Island is Sebatik Island, which is split in two by a straight east-west line across the centre of the island. The northern part lies in Malaysia and the southern half within Indonesia. The Indonesian portion has an area of 246.61 km² and had a population of 47,571 at the 2020 census, and 55,870 according the mid 2024 estimates, comprising five of the regency's districts.