The NH4991 Square Kilometre

NH4991 National Grid Square

Based in the Highlands and Islands region of Scotland.

NH4991 is within the post town of Ardgay, Ross-shire.

The square is within Highland council.

The Point of Origin (0,0) is 925.14 Kilometres away. This is where the National Grid starts around 80 kilometres west of the Isles of Scilly.

Ordnance Survey Maps for NH4991

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Map Series	link	Ordnance Survey
Explorer 1:25,000 441 Lairg, Bonar Bridge and Golspie		Buy Direct from the Ordnance Survey
Explorer 1:25,000 437 Ben Wyvis and Strathpeffer		Buy Direct from the Ordnance Survey
Explorer 1:25,000 440 Glen Cassley and Glen Oykel		Buy Direct from the Ordnance Survey
Landranger 1:50,000 20 Beinn Dearg	Shop for this map on amazon.co.uk

This extract is taken from the Ordnance Survey six-inch to the mile series surveyed from 1888-1913. The scale is 1:10,560.

The Square overlayed over the map represents the extent of NH4991 and the vertical and horizontal line divides the square into four quadrants

Dividing the NH4991 Square to get a six figure Grid Reference

A helpful reminder for calculating grid references is across the landing and up the stairs.

For example if your house was located in a square that in the fourth square across and sixth square up and you wanted to work out its six figure grid refence.

First, You would divide the four figure grid reference into three parts. NH , 49 and 91

Count across starting with zero. This would give you three. Make a note that X for Across (A Cross) = 3.

Count up starting with zero. This would give you five. Make a note that Y = 5.

So to put it together NH + 49 + 3 + 91 + 5 would give you the six figure grid reference of NH493915

NH	49		91
NH	49	3	91	5

A six figure grid reference would be accurate to 10 metres. To achieve a greater level of accuracy this 10 metre square would be divided into a grid 10 by 10 and the process repeated.

This would produce an 8 figure grid reference that would be accurate to a square metre!

Corner	Latitude	Longitude	Easting	Northing
South West Corner	57.882810	-4.548881	249000	891000
South East Corner	57.882810	-4.531399	250000	891000
North West Corner	57.892120	-4.548881	249000	892000
North East Corner	57.892120	-4.531399	250000	892000