I have a requirement where I need to convert a set of Geohash to KML files such that they can be used as areas to plot data by overlaying on map.
Is anyone aware of an open resource which can help me with this conversion.
Yes, there are a couple of options I can point you towards.
Using's PostGIS's ST_GeomFromGeoHash
ST_GeomFromGeoHash — Return a geometry from a GeoHash string. Return a geometry from a GeoHash string. The geometry will be a polygon representing the GeoHash bounds.
If no precision is specified ST_GeomFromGeoHash returns a polygon based on full precision of the input GeoHash string.
If precision is specified ST_GeomFromGeoHash will use that many characters from the GeoHash to create the polygon.
Also, here is a tool Geohash Converter which states
Simple and fast conversion from geohash to latitude/longitude and from latitude/longitude to geohash.