Grid reference is a system used to identify locations on a map, using a network of numbered vertical and horizontal grid lines. On a large scale map, a grid like this can be used to define an area or pinpoint a location. There is a series of vertical lines we call Eastings and horizontal lines we call Northings, these lines make up the grid. Eastings runs vertically or north to south and shows how far East you have travelled. Northings run horizontally or west to east and shows how far North you have travelled.

                                                               (Figure 1. Map of Sandy Point area, St. Kitts.) 

The two numbers on the vertical and horizontal lines add up to make four-figure grid reference.  For example on figure 1. Burt is found in grid 1029. Similarly, Brimstone Hill Fort is found in grid 1117. Remember, Eastings are always given first.

If we want to give an exact location we divide the grid into tenths (see 0920 on figure 1). When we do this we are finding to six-figure grid reference which gives the exact location of features on a map. For example, Sir Gillies Estate has a six-figure grid reference of 096205. Also the ruined tower is located in grid 103207.

There are some important points to remember about grid references:

§  Eastings are vertical lines that run from north to south, their numbers increase in values from west to east.

§  Northings are horizontal lines that run from east to west, their numbers increase in values towards the north.

§ When stating a grid reference, the easting is always
 given first.

§  The distance between one grid line and next may be divided into ten imaginary parts for stating locations precisely.