is a district located in Niigata Prefecture, Japan. As of July 1, 2019, the district has an estimated population of 4,190 and a density of 94.4 persons per km2. The total area is 44.38 km2. Towns Izumozaki History Before the Edo Period, Santō District was part of the now-defunct Koshi District. On April 1, 2005 the towns of Koshiji and Mishima merged into the city of Nagaoka. On January 1, 2006 the towns of Teradomari and Yoita, and the village of Washima were also merged into Nagaoka. After two successful mergers with Nagaoka during an eight-month period, the district has an estimated population of 5,565 and a density of 125.39 persons per km2. The total area is 44.38 km2. Districts in Niigata Prefecture