Ōmi (青海町 Ōmi-machi?) was a town located in Nishikubiku District, Niigata Prefecture, Japan.
Ōmi was located on the Japan Sea coast, about four hundred kilometres north-west of Tokyo. The town also had two additional neighborhoods, Oyashirazu and Ichiburi, located six kilometres and thirteen kilometres respectively further down the coast from the main part of Ōmi.
On March 19, 2005, Ōmi, along with the town of Nō (also from Nishikubiki District), was merged into the expanded city of Itoigawa.
The town was a classic case of rural decline now often found in modern Japan. Over a period of 30 years, the population had decreased from around 17,000 to 9,797 as of 2003, with a population density of 75.87 persons per km². The total area was 129.13 km². After graduating from high school, many young people are forced to move to major population centres for university or in search of work. This was reflected in the population, with the majority of residents aged over 35. Concurrently the number of students attending Ōmi Junior High School fell from 568 to below 300 over a period of 20 years.
Ōmi had many well-funded facilities, including regular local bus and train services (but only a few long-distance services), an indoor heated pool, gymnasium, baseball field, several small local parks, mountain camping sites, plus a new natural history museum, library, and performance hall seating 500 people.
However, there were only a few small local shops, supermarkets and restaurants, and no entertainment facilities. With the declining population many such facilities (such as the movie theatre and baseball stadium) were closed and demolished in recent years.