Sagamihara recorded net in-migration of 2,321 people in 2023, yet its population is projected to decline from about 725,000 in 2020 to about 682,000 in 2045. The planned Linear Chuo Shinkansen station at Hashimoto is a major opportunity, but a single development project may not be enough to stop natural decrease and aging across the city's broad territory.
Sagamihara population structure (2020 Census)
| Indicator | Value |
|---|---|
| Total population | 725,493 |
| Children aged 0–14 | 82,532 (11.4%) |
| Working-age population aged 15–64 | 435,860 (60.1%) |
| Population aged 65+ | 185,236 (25.5%) |
| Daytime population | 645,219 |
| Daytime/nighttime population ratio | 88.9% |
| In-migrants (2023) | 32,014 |
| Out-migrants (2023) | 29,693 |
| Net migration | +2,321 |
Population forecast: decline becomes clearer in the 2030s
| Projection year | Projected population |
|---|---|
| 2025 | 719,711 |
| 2030 | 710,265 |
| 2035 | 697,762 |
| 2045 | 682,037 (5.9% below 2020) |
Even with net in-migration, the city is projected to lose about 43,000 people by 2045
In 2020, Sagamihara had an aging rate of 25.5% and a working-age population share of 60.1%. Its daytime/nighttime population ratio was 88.9%, reflecting its role as a residential city with many residents commuting elsewhere. In 2023, however, 32,014 people moved in compared with 29,693 moving out.
The projected population falls to 710,265 in 2030, 697,762 in 2035, and 682,037 in 2045. The 2045 figure is about 5.9% below 2020, with the decline becoming clearer during the 2030s.
Separate Hashimoto's growth opportunity from the challenges of Tsukui and established residential areas
Hashimoto is served by the JR Yokohama and Sagami lines and the Keio Sagamihara Line and is the planned location of the Linear Chuo Shinkansen's Kanagawa station. Sagami-Ono is another major rail hub on the Odakyu Line, and both station areas have room for further residential and business concentration.
At the same time, Sagamihara spans industrial and logistics districts as well as the hilly and mountainous Tsukui area, so aging and transport conditions differ greatly across the city. The opening timing and spillover effects of the Linear Chuo Shinkansen remain uncertain, and there is no basis for rewriting the 2045 projection on the assumption that the railway will reverse the trend. Sagamihara must manage growth around stations and contraction across the city at the same time.
How to read these figures
The future figures shown here are projections, not observed outcomes. They may change depending on future births, deaths, in-migration, and out-migration.
The article is organized primarily around published statistical figures. Numerical values directly observable in the statistical tables should be distinguished from interpretations of background factors.
Summary: The Linear Chuo Shinkansen is a tailwind, but it will not automatically stop population decline
Sagamihara has significant development potential around Hashimoto, while its population is still projected to fall to about 682,000 by 2045. The Linear Chuo Shinkansen should not be treated as a universal solution for the whole city; station areas, established residential districts, and hilly or mountainous areas will require different approaches.
- 2020 population: about 725,000
- Net in-migration in 2023: 2,321 people
- 2045 projected population: about 682,000, down 5.9% from 2020
- Hashimoto's growth and aging across the broader city should be considered separately
Source: Published statistics listed in the Analysis notes at the end of this article
📊 Analysis notes
This article is based on the following statistical data.
- Statistics used: Statistics Bureau of Japan, Social and Demographic Statistics System (Population and Households) (Table ID: 0000020101, view on e-Stat)
- Area: Sagamihara
- Base year: 2020
- Data retrieved: June 6, 2026
- Notes: The article is organized primarily around published population projections. The projected values themselves should be distinguished from interpretations of the factors behind them.
Chart and table values have been independently aggregated and visualized from the statistical data above.
Table values have been organized from the statistical data above.