Boundary KML Downloader
Need a city, county or region outline for Google Earth, a GIS or a report? Search the place, check its boundary on the map, and download it as KML or GeoJSON — with the enclosed area computed from the outline.
By Aryan Khan, Founder & Editor · Updated October 2026
Search for an OSM polygon and inspect the matched name and returned geometry before downloading.
How to use Boundary KML Downloader
A place name in, a boundary file out:
Search for a place and retrieve the first polygon among up to five Nominatim matches. Download the returned geometry as KML or GeoJSON; the approximate spherical area is not an official land-area figure.
- 1Type the place name, as specifically as you can.
- 2Press “Get the boundary” and check it on the map.
- 3Download KML or GeoJSON.
What people use Boundary KML Downloader for
1. Reports and presentations
A clean jurisdiction outline drops into slides and PDFs without tracing screenshots. Pair with the Country Boundary Downloader when the report zooms out to nations.
2. GIS starting geometry
Service areas, sales territories and study extents all start from an administrative outline — download it here, then clip your data against it in QGIS or ArcGIS.
3. Google Earth projects
KML is Earth’s native tongue: the downloaded file opens as a placemark polygon you can style, label and fly to.
4. Checking a boundary claim
A vendor’s coverage map says ‘the whole county’. Download the county and overlay — the outline either agrees or the conversation changes.
Worked examples
A KML boundary is a Placemark holding a Polygon whose outerBoundaryIs ring lists longitude,latitude pairs around the place. The GeoJSON flavour carries the same outline as a Polygon or MultiPolygon feature — one geometry, two envelopes.
Returned MultiPolygon features can contain detached parts; their coverage depends on the source record. The map preview fits only the first outer ring.
KML or GeoJSON — which download?
Same outline, different ecosystems.
| Format | Open it with | Best for |
|---|---|---|
| KML | Google Earth, Google My Maps | Sharing, presenting, Earth projects |
| GeoJSON | QGIS, web maps, code | GIS work, web development, data pipelines |
| Either | Both carry WGS84 lon/lat | Coordinates are longitude first in both files |
Boundaries come from open map data (OpenStreetMap’s administrative records): excellent for general work, while legal jurisdiction questions belong to official survey sources.
How to interpret the result
The most common errors come from using a correct result to answer the wrong geographic question. Keep these points in mind for Boundary KML Downloader:
- Validate before trusting exports from unfamiliar tools — open them in a local viewer and check feature counts, bounding boxes and a few property rows. A wrong-axis or swapped-coordinate export is far easier to catch on a map than in a spreadsheet.
- For big CSVs, fix the coordinate columns first and map a sample before mapping everything: auto-detection is good but not magical, and one swapped column renders a beautiful map of the wrong ocean.
Limits & appropriate use
File formats support different combinations of geometry, timestamps, properties and styling. Converting between them can lose information, so keep the original and inspect the output before sharing or using it.
Capabilities differ by workspace: check the accepted format and the operations actually offered on this page. Some tools process files locally but may request map tiles or other services over the network; large or specialised datasets may require dedicated GIS software.
- Cadastral/legal formats → jurisdictional land-registry exports.
- Point clouds and rasters → desktop GIS with proper spatial indexes.
- Certified tracks (evidence, insurance) → chain-of-custody originals, untouched.
Data & methodology
Nominatim polygon_geojson retrieval plus Chamberlain–Duquette spherical area computation and the site's KML writer.
For source details, licences and model limitations, see Data Sources and Methodology.
Key terms worth knowing
- GeoJSON
- JSON geographic format; the web-mapping native dialect.
- KML
- XML format from the Google Earth era, with styling and ExtendedData.
Editorial guidance: MapBench explains the method and limitations so the tool can be used as a transparent reference, not as a black-box answer. For legal boundaries, safety-critical routing, surveying, engineering, regulated decisions or official statistics, verify the result with the responsible authority or a qualified professional.
Category: Map Files. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
Method, assumptions & limits
- This tool’s method
- Nominatim polygon_geojson retrieval plus Chamberlain–Duquette spherical area computation and the site's KML writer.
- Before relying on the answer
- Inspect the accepted file format and the fields reported by this specific tool. Keep a copy of the original file before converting or editing it.
- What the result cannot establish
- File geometry and recorded timestamps can be incomplete. Verify row or point counts and inspect the exported file in your target application.
Coverage: Worldwide. Search, basemap and external data requests may use third-party services; browser-based does not mean every operation is offline. Read the source and licence notes, calculation methodology and privacy policy. If a result looks inconsistent, report a correction with the inputs and mode used.
Frequently asked questions
Clear answers about the calculation, accuracy and appropriate use.
Where does the boundary come from?
OpenStreetMap, served by Nominatim with full polygon geometry — the same outline the map draws.
Is the area exact?
It is computed from the outline geometry (spherical polygon area) — good for planning; legal areas come from the authority's own survey.
Is my uploaded map file sent to a server?
Where a page says browser-first or local processing, the file is handled in your browser. Check the individual tool note for any external-service dependency.
What should I do if a file will not load?
Check that the file type is supported, the structure is valid and the file is within the stated size limits. Converting to GeoJSON, GPX, KML or CSV can also help.
Will converting a file preserve every property?
Not always. Geographic formats support different geometry, style and metadata features, so inspect the output before relying on it.
Which places can I download?
Cities, counties, regions and other administrative areas present in the open boundary data — from US counties and German Landkreise to French communes. Very small or unmapped jurisdictions may not have a recorded outline.
What file types are offered?
KML for the Google Earth world and GeoJSON for GIS and web work. Both hold the same WGS84 outline; only the envelope differs.
Can I download several places at once?
One place per download keeps files clean and named. For a set, download each and merge in your GIS — boundaries combine trivially as features.
Why does the outline look simplified on the map?
The map preview fits the first outer ring only. The export contains the returned geometry, including other polygon parts where present.
Does it include ZIP code boundaries?
ZIPs are postal, not administrative — the dedicated ZIP boundary tools on this site cover that family. Administrative places live here.
Can I edit the boundary after downloading?
Yes — the file is yours. Edit vertices in QGIS or Google Earth; just remember an edited outline is your geometry, not the source’s record.
What about disputed or changing boundaries?
The file reflects the open data’s current documented position. Annexations and disputes resolve in the data over time, not in this downloader.
Related tools and resources
Nations: the Country Boundary Downloader; your own files measured: the GeoJSON Area Calculator and GeoJSON Bounding Box Calculator.
More free tools
Sources, methodology & editorial trust
- ✓ Browser-first processing where supported
- ✓ External sources are documented
- ✓ No account required for public tools
- ✓ Review data sources
Calculations are documented with their assumptions, limitations and source context rather than presented as unexplained answers.
Reviewed and maintained by Aryan Khan, Founder & Editor of MapBench.
Part of our gis files hub
Boundary KML Downloader sits in the gis files cluster, alongside 64 other tools that answer neighbouring questions with different methods or datasets. It also belongs to the CSV, KML & WKT family.
You may also need
When this answer is only part of the job, these clusters cover the next step.
Read the guide behind this tool
KML vs. GeoJSON vs. GPX: Choosing the Right Map File Format — The practical differences between three common geographic file formats — when to use each, what can be lost in conversion, and how to move between them.