Municipalities Within a Radius in Japan

Set the center and the distance

Municipalities inside the radius

Center

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Nearest municipality

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Count by prefecture

Two ways to set the center

Either one produces the same kind of result.

Use your current location

Pressing “Get my location” makes the browser ask for permission. Once granted, the list is built immediately around that point. Indoors, or on a desktop machine, the position is estimated from Wi-Fi networks or your IP address, so the error can range from a few hundred metres to several kilometres. If the center lands somewhere unexpected, set it by municipality name instead.

Search for a municipality

Type part of a name to get suggestions. Romaji, kanji, hiragana, katakana and the five-digit local government code all work: “Matsumoto”, “まつもと” and “20202” all reach Matsumoto-shi. Selecting a suggestion puts that municipality's reference point at the center. Names that repeat across the country, such as Fuchu-shi or Date-shi, are shown with their prefecture so you can tell them apart.

There is no address or place-name lookup, because the page deliberately avoids calling any outside mapping service. The link from “Copy link to these settings” does carry the coordinates, so a result centred on a station or a building — finer than a whole municipality — can still be reopened from a link.

Reading the result

The table is sorted by distance. “Distance” is the straight line between the center and the municipality's reference point, and “Direction” is the compass bearing from the center on a 16-point scale. Below the table, the count per prefecture shows at a glance whether the radius crosses a prefectural border.

“On foot” and “By car” are there to make the distance concrete. Walking uses 4.8 km/h (the 80 metres per minute of Japanese property listings) and driving uses 30 km/h (a rough figure for urban surface roads), applied straight to the straight-line distance. Real routes are longer, and lights, congestion and hills all add to them, so the figures are a best case. With an expressway, driving time is roughly half. The same pair of figures for the radius itself appears under the distance field.

“Copy the list” writes the rank, name, distance, direction and both travel times as tab-separated text, which pastes into a spreadsheet as separate columns. The link from “Copy link to these settings” carries the coordinates and the distance, so the same result can be reopened later. Above 500 matches, both the table and the copied list stop at the nearest 500.

What it is useful for

Drawing up a shortlist of places to live. A 30 km radius around a workplace brings up every municipality worth looking at. Working from a rail map tends to keep you on one line; working from distance puts neighbouring lines, and neighbouring prefectures, on the same footing.

Defining a delivery, sales or service area. If the rule is “within 50 km of the depot”, knowing which municipalities that covers makes it easier to split territory or set shipping bands. Actual driving distance depends on the road network, so treat the straight-line list as a starting point.

Getting a sense of the area affected by an event. Centring on an epicentre or a facility and widening the radius shows which municipalities are closest, in order. Official evacuation information and damage assessments come from the municipalities themselves and the Japan Meteorological Agency.

Example: within 10 km of Tokyo Station

With the center at Tokyo Station (35.6812°N, 139.7671°E) and a distance of 10 km, 15 municipalities match — all of them special wards of Tokyo. Kawaguchi-shi in Saitama and Kawasaki-shi in Kanagawa are still outside at 10 km. Walking and driving estimates are included.

Example: how many municipalities fall inside each radius

The same radius covers very different numbers of municipalities depending on where you put the center. Urban areas are divided finely; in rural areas a single city can fill the whole circle. Seven representative centers:

Osaka beats Tokyo at 10 km because the cities around it are small and numerous. Sapporo and Sendai are low because the wards of those cities, and the towns around them, cover large areas. A rule expressed as “within X km” therefore reaches several times more municipalities in one part of the country than in another.

Where the data comes from

The reference points are derived from the address master published by geolonia under CC BY 4.0, which contains a representative point for every town-level address. That data in turn comes from the Location Reference Information of the Ministry of Land, Infrastructure, Transport and Tourism, Japan Post's postal code data, and the Address Base Registry of the Digital Agency.

For each municipality, the median latitude and median longitude of its town points are computed, and the real town point closest to that median becomes the reference point. A plain average would place the point out at sea for municipalities with islands or detached parcels. The result is 1,894 entries, counting the wards of designated cities and Tokyo's 23 special wards individually.

Distances are great-circle distances from the coordinates (haversine formula, Earth radius 6,371 km). Within Japan, the difference from a rigorous ellipsoidal calculation stays around 0.5%. Mergers and renamings are not picked up automatically; the data is refreshed by hand.

How your location is handled

The current position comes from the browser's standard Geolocation API, and the resulting coordinates are used only inside this page. Nothing is sent to a server and nothing is stored. After the municipality data is fetched once, filtering and sorting need no network access at all. The link produced by “Copy link to these settings” does contain the coordinates, so check what you are sharing before you send it.

Location permission can be revoked at any time in the browser's settings. Without it, searching by municipality name does the same job. Site-wide handling is described in the privacy policy.

Related pages

For regional figures, gold, exchange rate and petrol prices tracks national averages day by day, and the income thresholds simulator covers the tax and insurance limits that apply to part-time work in Japan. It is also useful for checking nearby municipalities after a disaster — see the Kumamoto earthquake news roundup for related information.

Frequently asked questions

Is this straight-line distance or road distance?

Straight-line distance. The page computes the great-circle distance between two points, treating the Earth as a sphere with a radius of 6,371 km. Travelling by road or rail always takes longer, and can be more than twice as far where mountains or water are in the way. The tool is meant for drawing up a list of candidate areas, not for estimating travel time.

Which point inside a municipality is the distance measured from?

Each municipality has a single reference point. It is the town-level point closest to the median of every town point in that municipality. It is not the city hall. In municipalities with a large area, the far edges can be more than 20 km away from the distance shown.

Is my location sent anywhere?

No. The current location comes from the browser's own Geolocation feature, and both the coordinates and the distance calculation stay inside this page. Nothing is sent to a server and nothing is stored. The municipality data is fetched once, after which the page works without any network access.

How many municipalities are included?

1,894. The wards of designated cities such as Sapporo-shi Chuo-ku and the 23 special wards of Tokyo are each counted as one entry. A few small islands and the villages of the Northern Territories have no address data and are not included.

How are the walking and driving times calculated?

The straight-line distance is simply divided by 4.8 km/h for walking (the 80 metres per minute used in Japanese property listings) and by 30 km/h for driving (a rough figure for urban surface roads). Real routes are longer than a straight line, and traffic lights, congestion and terrain all add to them, so treat the figures as a best case. Where an expressway is available, driving time is roughly half of what is shown.

Why does nothing appear inside the radius?

The distance is too small. Because each municipality has only one reference point, a radius of 2 to 3 km can exclude even the municipality you are standing in. Start at around 20 km and widen from there.

Distances and counts are calculated automatically and are for reference only. Where the exact boundary matters — subsidy eligibility, shipping zones — check the definition used by the scheme and the announcements of the municipalities concerned.