Nagano長野県
Oomachi 大町市
Data last updated:
Oomachi, Nagano, Japan has a population of 23,956 (2025 national census). IPSS projections estimate 21,851 by 2030 and 14,411 by 2050 (a decrease of about 44.6% from 2020), with the share of residents aged 65+ rising from 38.9% in 2020 to 51.7%.Sources: Japan Census (Statistics Bureau), IPSS Regional Population Projections (2023)
2025
(Census)
23,956
2030
(Projection)
21,851
▼ -16.1%
2040
(Projection)
17,984
▼ -30.9%
2050
(Projection)
14,411
▼ -44.6%
Change vs. 2020 census
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Other municipalities in Nagano (長野県)
Data Sources
- Portal Site of Official Statistics of Japan (e-Stat)（https://www.e-stat.go.jp/）
- National Institute of Population and Social Security Research (IPSS), Regional Population Projections (2023 ed.)
* This service uses the e-Stat API but its content is not guaranteed by the Japanese government.
Oomachi Population Table (1980–2050)
Population by year: national census results (restated to current municipal boundaries) and IPSS (2023) projections based on the 2020 census.
| Year | Population | vs 2020 | Type |
|---|---|---|---|
| 1980 | 36,083 | ▲ +38.6% | Census |
| 1985 | 35,460 | ▲ +36.2% | Census |
| 1990 | 34,300 | ▲ +31.8% | Census |
| 1995 | 33,655 | ▲ +29.3% | Census |
| 2000 | 33,550 | ▲ +28.9% | Census |
| 2005 | 32,145 | ▲ +23.5% | Census |
| 2010 | 29,801 | ▲ +14.5% | Census |
| 2015 | 28,041 | ▲ +7.7% | Census |
| 2020 | 26,029 | — | Census |
| 2025 | 23,956 | ▼ -8.0% | Census |
| 2030 | 21,851 | ▼ -16.1% | Projection |
| 2035 | 19,890 | ▼ -23.6% | Projection |
| 2040 | 17,984 | ▼ -30.9% | Projection |
| 2045 | 16,147 | ▼ -38.0% | Projection |
| 2050 | 14,411 | ▼ -44.6% | Projection |
About Oomachi
Overview
Oomachi (大町市) is a municipality in Nagano, Japan, with a population of 23,956 as of 2025.
Population Projection of Oomachi
According to projections by Japan's National Institute of Population and Social Security Research (IPSS), Oomachi's population is expected to reach 21,851 by 2030 (-16.1%), 17,984 by 2040 (-30.9%), and 14,411 by 2050 (-44.6%). A significant population decline is projected over the next three decades.
Aging Rate of Oomachi
The aging rate (percentage of residents aged 65 and over) is 38.9% as of 2020 and is projected to rise to 51.7% by 2050. More than half of residents will be seniors, placing the town in the "marginal municipality" category.
National Comparison
Oomachi is experiencing one of the faster rates of population decline in Japan.
National and Prefectural Rank
- Population decline rate: Ranked #542 out of 1903 municipalities nationwide.
- Aging rate in 2050: Ranked #444 out of 1903 nationwide.
- Population size: Ranked #1008 out of 1917 nationwide.
- Related: National rankings / All municipalities in Nagano
Earnings in Nagano (長野県): Average salary in Nagano (長野県) by age, gender and company sizejpsalary / MHLW Basic Survey on Wage Structure