Kanagawa神奈川県
Ooi 大井町
Data last updated:
Ooi, Kanagawa, Japan has a population of 17,100 (2025 national census). IPSS projections estimate 16,272 by 2030 and 13,312 by 2050 (a decrease of about 22.3% from 2020), with the share of residents aged 65+ rising from 29.1% in 2020 to 43.1%.Sources: Japan Census (Statistics Bureau), IPSS Regional Population Projections (2023)
2025
(Census)
17,100
2030
(Projection)
16,272
▼ -5.0%
2040
(Projection)
14,809
▼ -13.5%
2050
(Projection)
13,312
▼ -22.3%
Change vs. 2020 census
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Other municipalities in Kanagawa (神奈川県)
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.
Ooi 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 | 12,832 | ▼ -25.1% | Census |
| 1985 | 14,006 | ▼ -18.2% | Census |
| 1990 | 14,895 | ▼ -13.0% | Census |
| 1995 | 15,599 | ▼ -8.9% | Census |
| 2000 | 16,582 | ▼ -3.2% | Census |
| 2005 | 17,530 | ▲ +2.3% | Census |
| 2010 | 17,972 | ▲ +4.9% | Census |
| 2015 | 17,033 | ▼ -0.6% | Census |
| 2020 | 17,129 | — | Census |
| 2025 | 17,100 | ▼ -0.2% | Census |
| 2030 | 16,272 | ▼ -5.0% | Projection |
| 2035 | 15,560 | ▼ -9.2% | Projection |
| 2040 | 14,809 | ▼ -13.5% | Projection |
| 2045 | 14,062 | ▼ -17.9% | Projection |
| 2050 | 13,312 | ▼ -22.3% | Projection |
About Ooi
Overview
Ooi (大井町) is a municipality in Kanagawa, Japan, with a population of 17,100 as of 2025.
Population Projection of Ooi
According to projections by Japan's National Institute of Population and Social Security Research (IPSS), Ooi's population is expected to reach 16,272 by 2030 (-5.0%), 14,809 by 2040 (-13.5%), and 13,312 by 2050 (-22.3%). A significant population decline is projected over the next three decades.
Aging Rate of Ooi
The aging rate (percentage of residents aged 65 and over) is 29.1% as of 2020 and is projected to rise to 43.1% by 2050. Over 40% of residents will be elderly, significantly affecting healthcare and social services needs.
National Comparison
Ooi's population decline rate exceeds the national average.
National and Prefectural Rank
- Population decline rate: Ranked #1283 out of 1903 municipalities nationwide.
- Aging rate in 2050: Ranked #1014 out of 1903 nationwide.
- Population size: Ranked #1134 out of 1917 nationwide.
- Related: National rankings / All municipalities in Kanagawa
Earnings in Kanagawa (神奈川県): Average salary in Kanagawa (神奈川県) by age, gender and company sizejpsalary / MHLW Basic Survey on Wage Structure