diff --git a/NuWeather/README.md b/NuWeather/README.md
index f16f0cb..8019805 100644
--- a/NuWeather/README.md
+++ b/NuWeather/README.md
@@ -58,3 +58,15 @@ config plugins.NuWeather.DBAddressingMode nicks
 5) Load the plugin again for these changes to take effect.
 
 (If you're comfortable with re-creating your database from scratch, the other options tell NuWeather to save location by Supybot account (the default) or ident@host.)
+
+## Location lookup (Geocoding) backends
+
+* Apixu provides weather lookup by place name directly, and does not need further configuration.
+* Dark Sky requires a separate lookup to translate place names into GPS coordinates, a process known as **geocoding**.
+
+The default backend for geocoding is [OpenStreetMap's Nominatim]((https://nominatim.openstreetmap.org/)) service, and can be configured via the `plugins.NuWeather.geocodeBackend` option.
+
+Other supported options include [Google Maps](https://developers.google.com/maps/documentation/geocoding/start) and [OpenCage](https://opencagedata.com/),
+which may provide more relevant results for North America (e.g. U.S. ZIP codes). These services both require API keys: [Google Maps](https://developers.google.com/maps/documentation/geocoding/get-api-key) (credit card required) | [OpenCage](https://opencagedata.com/api)
+
+API keys for geocoding backends are configured as `plugins.NuWeather.apikeys.BACKENDNAME`.