Read this first : briefest of introductions
OS maps have what you want
Whether you are interested in family history, transport history, walking, map collecting or a thousand other activities, this site should provide something of interest and use. Most people use old Ordnance Survey maps to support a particular interest : where the family came from, pre-Beeching railways, the line of a footpath and so on.
A brief introduction to Ordnance Survey maps
Ordnance Survey maps fall into three main groups : Large scale maps, Medium scale maps and Small scale maps.
Large scale maps
These are very detailed and can show individual houses, field boundaries, lamp posts and so on. They usually come as flat sheets and are seldom folded into covers.
Small scale maps
These are much less detailed, but show a bigger area of land on a single sheet of paper. The one-inch scale (and today, the 1:50,000 scale) is the most popular small scale map and goes back to 1801. Roads, railways, woods, rivers and buildings are shown, but only in sufficient detail to enable someone to find their way around.
The half-inch and quarter-inch maps give even less detail, but show an even greater area, and are often used by motorists and cyclists.
Ten-mile maps (ten miles to one inch) are very generalised and with only two sheets covering England, Wales and Scotland, can show a lot of regional information on a single sheet.
Medium scale maps
The 1:25,000 scale falls between the large and small scales. These are the most popular maps for walkers and have been in general use since the late 1940s. The current Explorer (orange covers) and earlier Pathfinder (green covers) maps are of this scale.