Chiba千葉県
Isumi いすみ市
Data last updated:
Isumi, Chiba, Japan has a population of 32,463 (2025 national census). IPSS projections estimate 29,674 by 2030 and 20,218 by 2050 (a decrease of about 43.1% from 2020), with the share of residents aged 65+ rising from 42.4% in 2020 to 58.0%.Sources: Japan Census (Statistics Bureau), IPSS Regional Population Projections (2023)
2025
(Census)
32,463
2030
(Projection)
29,674
▼ -16.5%
2040
(Projection)
24,692
▼ -30.5%
2050
(Projection)
20,218
▼ -43.1%
Change vs. 2020 census
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Other municipalities in Chiba (千葉県)
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.
Isumi 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 | 42,816 | ▲ +20.5% | Census |
| 1985 | 43,453 | ▲ +22.3% | Census |
| 1990 | 43,431 | ▲ +22.2% | Census |
| 1995 | 43,547 | ▲ +22.5% | Census |
| 2000 | 42,835 | ▲ +20.5% | Census |
| 2005 | 42,305 | ▲ +19.0% | Census |
| 2010 | 40,962 | ▲ +15.2% | Census |
| 2015 | 38,594 | ▲ +8.6% | Census |
| 2020 | 35,544 | — | Census |
| 2025 | 32,463 | ▼ -8.7% | Census |
| 2030 | 29,674 | ▼ -16.5% | Projection |
| 2035 | 27,150 | ▼ -23.6% | Projection |
| 2040 | 24,692 | ▼ -30.5% | Projection |
| 2045 | 22,364 | ▼ -37.1% | Projection |
| 2050 | 20,218 | ▼ -43.1% | Projection |
About Isumi
Overview
Isumi (いすみ市) is a municipality in Chiba, Japan, with a population of 32,463 as of 2025.
Population Projection of Isumi
According to projections by Japan's National Institute of Population and Social Security Research (IPSS), Isumi's population is expected to reach 29,674 by 2030 (-16.5%), 24,692 by 2040 (-30.5%), and 20,218 by 2050 (-43.1%). A significant population decline is projected over the next three decades.
Aging Rate of Isumi
The aging rate (percentage of residents aged 65 and over) is 42.4% as of 2020 and is projected to rise to 58.0% by 2050. More than half of residents will be seniors, placing the town in the "marginal municipality" category.
National Comparison
Isumi is experiencing one of the faster rates of population decline in Japan.
National and Prefectural Rank
- Population decline rate: Ranked #598 out of 1903 municipalities nationwide.
- Aging rate in 2050: Ranked #172 out of 1903 nationwide.
- Population size: Ranked #861 out of 1917 nationwide.
- Related: National rankings / All municipalities in Chiba
Earnings in Chiba (千葉県): Average salary in Chiba (千葉県) by age, gender and company sizejpsalary / MHLW Basic Survey on Wage Structure