Niigata prefecture stretches about 240 km along the Sea of Japan from southwest to north east, with a coastal plain between the mountains and the sea.
The town of Oguni from Kariwa District, the village of Yamakoshi from Koshi District, the town of Nakanoshima from Minamikanbara District and the towns of Koshiji and Mishima from Santo District merged into the city of Nagaoka.
Niigata is a source for crude oil, not often found on the Japanese islands.
It is the second largest city in the prefecture, behind the capital city of Niigata.
Nagaoka is located at longitude 138° E and latitude 37° N. The size of Nagaoka increased on April 1, 2005, when the town of Oguni, the village of Yamakoshi, the town of Nakanoshima, the town of Koshiji, and the town of Mishima in were absorbed into the city of Nagaoka.
Nagaoka is located in the center of Niigata prefecture and the surrounding Chuetsu region.