Ordnance Survey Pathfinder Maps (Green Covers)
1:25 000 Scale (4cm to 1km or 2 1/2 inches to 1 mile)
The Pathfinder series of 1:25 000 Scale maps originally covered England, Scotland and Wales.
There were 1200 maps in total and were predominantly rectangular 20km (East to West) by 10km (North to South) sheets.
They have now been replaced by the Ordnance Survey Explorer Series (orange covers) and are no longer in print.