geonames-mcp-server

@cyanheads/geonames-mcp-server Search GeoNames places, walk admin hierarchies, reverse geocode, get postal codes and country info via MCP. STDIO or Streamable HTTP. 8 Tools

Public Hosted Server: https://geonames.caseyjhand.com/mcp

Overview

The GeoNames gazetteer: 13M+ places worldwide, linked into an administrative tree from continent to neighborhood. Search places, read full records, walk the admin hierarchy, reverse geocode coordinates, look up postal codes, and read country facts.

Tools

Capability reference

geonames_search_places tool

• query (up to 200 characters) compared per match: name_required (default), any_field, exact_name, or name_prefix; filters countries (up to 10, by ISO alpha-2, alpha-3, or numeric code), adminCode1–adminCode4, featureClasses, featureCodes (up to 20), cities (cities1000 / cities5000 / cities15000), and boundingBox. A call needs query or one of countries, featureClasses, featureCodes, boundingBox
• A listed country also returns the territories GeoNames files under it (GB also returns IM, GG, JE, and GS), each place under its own countryCode; the notice names any country on the page that countries does not list
• adminCode1–adminCode4 search inside an admin division by its GeoNames code, as geonames_get_place and geonames_reverse_geocode return it in adminLevels (countries: ["US"], adminCode1: "TX", featureCodes: ["AIRP"] lists Texas airports). Codes are case-insensitive and zero padding counts (02, not 2); they are not ISO 3166-2 or postal codes (Bavaria is 02, not BY). Each needs exactly one country, and levels 2–4 need adminCode1
• limit 1–1,000 (default 10), held to 100 per call with a notice when more remain; offset 0–5000, orderBy relevance or population (omitted, GeoNames' own order); returns totalCount, effectiveQuery, and nextOffset
• featureClasses, featureCodes, and cities (class P only) intersect: with both lists set, each code's class must be listed and each listed class needs a code; beside cities, only class P and its codes. Anything else fails as feature_filter_mismatch
• Fails before any request with query_or_filter_required, query_required, unknown_country_code, unknown_feature_code, admin_code_unscoped, feature_filter_mismatch, or invalid_bounding_box

geonames_get_place tool

• One geonameId; an unknown id returns found: false with guidance
• Returns adminLevels 1–5 (code, name, geonameId), timezone (UTC offsets on 1 January and 1 July), bounding box, recorded and DEM elevation, population, Wikipedia URL, alternateNames, postalCodes, links, and identifiers (IATA, ICAO, FAA, Transport Canada, UN/LOCODE, Wikidata)
• The timezone is the zone GeoNames associates with the record. On a record with no country (an ocean, a sea, a continent) a notice says so and gives the geonames_reverse_geocode call for the time at its coordinates
• postalCodes lists the codes GeoNames links to the feature, which can be fewer than geonames_find_postal_codes returns for the place
• nameLanguages (up to 20 tags; zh also matches zh-CN) filters alternateNames only

geonames_get_hierarchy tool

• One geonameId; chain runs from Earth and its continent through the country and admin divisions down to the feature, skipping levels it does not sit under
• Each level carries geonameId, feature class and code, country and first-level codes, coordinates, and population; an unknown id returns found: false

geonames_get_children tool

• hierarchy: administrative (default), tourism (islands, coasts, and their municipalities; almost all in Spain), or dependency (a country's dependent territories). Children are mostly admin divisions (class A) and populated places (class P); continents and coasts are class L, islands class T
• GeoNames answers a tourism or dependency request with the administrative children when the feature has no such tree. The tool compares the two lists and sets sameAsAdministrative, with a notice, when they match; the rows stay, since a real tree can match too
• Fetches up to 1,000 children per parent once and caches them, so nameContains, limit (1–1,000, default 100, held to 500 per call with a notice when more remain), and offset cost no extra credits; a notice says when GeoNames lists more. A nameContains with no letter or digit fails before any request as name_contains_unsearchable
• An unknown id returns found: false; a leaf returns an empty children list with a notice

geonames_reverse_geocode tool

• lat / lng resolve to country and adminLevels (down to ADM5, each with its geonameId and ISO 3166-2 subdivision code where one exists) or, offshore, the ocean
• coastalBufferKm (0–50, default 0) matches the nearest country within that distance when none contains the point, for harbor, pier, and shoreline fixes; a buffered match carries country.distanceInKm, and the nearby and timezone lookups keep the exact point
• nearby lists the nearest populated places (nearbyLimit 0–1,000, default 5, held to 50 per call with a notice when more lie within the radius; radiusKm up to 300, default 20; optional cities tier) or, when featureClasses / featureCodes is set, the nearest features of that type; nearbyKind says which. featureClasses and featureCodes intersect
• When more than 50 lie within the radius, the notice prints the geonames_search_places call, with a boundingBox enclosing the radius, that lists them, up to the search's 5,100-row reach. The search returns rows by relevance, not distance, so read every page and keep the rows within radiusKm
• Fails before any request with conflicting_filters (cities with a feature filter), unknown_feature_code, or feature_filter_mismatch (a code whose class is not listed, or a listed class with no code)
• includeTimezone adds the IANA id, UTC offsets, local time, sunrise, and sunset (offsets only offshore, where both dates are reported at the standard offset)

geonames_find_postal_codes tool

• mode: code (needs postalCode), place_name (needs placeName), or nearby (needs lat and lng; radiusKm up to 30, default 10); a missing field, or countries or an offset above 0 in nearby, fails as mode_fields_mismatch
• countries filter for code and place_name, by ISO alpha-2, alpha-3, or numeric code (the 250 country codes plus the retired AN, CS, and YU; any other, such as EL or ZZZ, fails as unknown_country_code)
• A listed country also returns the territories GeoNames files under it (GB also returns IM, JE, and GG), each postal code under its own countryCode; the notice names any country on the page that countries does not list
• limit 1–1,000 (default 10), held to 100 per call with a notice when more remain; code and place_name page with offset 0–5000 and return nextOffset while more rows remain below offset 5000; GeoNames reports no total, so truncated says whether more rows exist, never how many
• Covers 122 countries; Ireland returns only Eircode routing keys and Malta only letter prefixes
• Admin codes on postal rows come from the postal dataset and can differ from the gazetteer's (Bavaria is BY here, 02 in search), so they are not geonames_search_places filters

geonames_get_countries tool

• Up to 250 countries by ISO alpha-2, alpha-3, or numeric code, a continent, nameContains, or no filter for all 250; limit 1–1,000 (default 50), held to 250 per call, with offset; a nameContains with no letter or digit fails before any request as name_contains_unsearchable
• Rows carry ISO and FIPS codes, geonameId (the starting point for geonames_get_children), capital, population, area, continent, languages, currency, postal-code format, and mainland bounding box; unknown codes land in notFound

geonames_list_reference tool

• topic: feature_classes (9), feature_codes (684, filterable by featureClass), or postal_countries (122, with each country's code range and count); featureClass with another topic fails as filter_not_applicable
• nameContains, limit 1–1,000 (default 100, held to 700 per call, which fits every topic), and offset; feature classes and codes are bundled and spend no credits. A nameContains with no letter or digit fails before any request as name_contains_unsearchable

Features

Built on [@cyanheads/mcp-ts-core](https://github.com/cyanheads/mcp