Where was North West Frontier filmed?

Filming locations

• Studios & sets Pinewood Studios England British film studio and television studio situated in Iver Heath, Buckinghamshire, England

  “By July 1959, the production had moved to Pinewood Studios in England to complete interior scenes inside the Maharajah's palace, ambassador's residence and the rail carriage.” Wikipedia

• Landmarks & buildings station Iznalloz Spain Railway station in Iznalloz, Spain
• Streets & squares Puente del Anchurón Spain Bridge in Spain

Also per Wikipedia's article

The Wikipedia article names 12 more places. Each links to the sentence that says so.

Recorded only at country level

Also filmed in Spain, but the exact places are not known, so they are not on the map.

Also shot in these places