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Explorer 300 Challenge

A cache by TrainSPLOTer Send Message to Owner Message this owner
Hidden : 12/30/2014
5 out of 5
1.5 out of 5

Size: Size: micro (micro)

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Geocache Description:

This is another in the Explorer Challenge series originally conceived by the PetersfieldPoodlePosse

The cache is at the published location, but to log it you must have found caches in at least 110 different grid squares on the Ordnance Survey Explorer 300 map.

Although the cache is called the Explorer 300 Challenge you only have to have found a cache in 110 of the 860 kilometre grid squares covered by the map. To qualify the 110 caches must be in a different British Ordnance Survey grid square as depicted on the OS Explorer 300 Howardian Hills & Malton East map.
The caches can be of any type, previous finds qualify (including those finds now archived and events attended (even if you were the host)), in fact just about any cache other than those you have placed yourself can be counted.
To find out more about this and other Explorer Challenge caches, go to has been created to complement the cache series.
The grids on the map "start" to the north west of Ampleforth at SE 57000 80000 and finish to the north west of Driffield at SE 00000 60000.

From personal experience I know how time consuming trying to determine which of 860 squares of an OS map a cache qualifies for, although of course the British Grid reference is given at the top of each cache page just below the main co-ordinates shown in bold, as circled below.

For the purposes of this challenge the published co-ordinates of all caches, including Mystery/Puzzle and Multi caches are those that are to be used when determining which square a cache counts towards

To help those of you that want to plan your finds a GSAK Macro has been written which produces a web page of your finds, example output shown below.

Any finds without proof of qualification will of course be deleted! Have fun!

Please REPLACE the cache exactly as found to ensure it cannot be spotted.
Many many thanks to PetersfieldPoodlePosse who created all the difficult stuff on this page leaving me to add these few specific items of information.

Additional Hints (Decrypt)

Pyrna, hahfrq, fnzcyr ghor, ynxr fvqr, uvqqra vafvqr gur vil pbirerq gerr, pbirerq ol n fgbar

Decryption Key


(letter above equals below, and vice versa)



20 Logged Visits

Found it 6     Didn't find it 3     Write note 5     Temporarily Disable Listing 1     Enable Listing 1     Publish Listing 1     Needs Maintenance 1     Owner Maintenance 1     Post Reviewer Note 1     

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**Warning! Spoilers may be included in the descriptions or links.

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Coordinates are in the WGS84 datum

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