Numbering County Series Maps

Six-Inch (1:10560 scale) Full Sheets

Most First Edition six-inch maps cover an area on the ground 6 miles east to west and 4 mile north to south. They are identified by the county name and a number, eg Essex 16. This number is sometimes shown in Roman numerals.

On the indexes, the area covered by each six-inch full sheet is defined by a heavily lined rectangle.

Six-Inch Quarter Sheets

Some First Edition six-inch maps and, with some exceptions, the subsequent editions of all the six-inch maps, were produced as quarter sheets, covering an area on the ground 3 miles east to west and 2 miles north to south.

Each sheet is identified by the county name and number, followed by the appropriate quadrant NW, SW, NE or SE, eg Essex 16 NW.

1:2500 Scale (or Twenty-Five-Inch) Plans

There are sixteen 1:2500 scale county series plans within each six-inch full sheet. Each 1:2500 scale plan covers an area on the ground 1 1/2 miles east to west and 1 mile north to south, and is identified by its number within the six-inch full sheet, eg Essex 16/5.

NB: Always mention the county by name when giving reference numbers for County Series Maps and Plans.