Lough Muckno Peace Park in Castleblayney was originally part of the estate of the Blayney family from whom the town of Castleblayney takes its name. The twelfth Lord Blayney, the last to hold the title, sold the estate in 1853 to Henry Thomas Hope, after whom Hope Castle is named.
Hope gave his name to the internationally known Hope Diamond, which had been cut from the Tavernier, the largest blue diamond in the world. The diamond had formed part of the French Crown Jewels but was stolen during the French Revolution. It later turned up at an auction in London and was bought by Henry Thomas. It was reputed to be unlucky however and Henry Thomas disposed of it in 1867.
The Hope family had fallen on lean times by 1916 and sold out to return to England. Hope Castle up until recently housed a restaurant and lounge. It is currently closed and undergoing extensive refurbishment. The grounds of the estate now form the wonderfully scenic Lough Muckno Peace Park.
LETTERBOXING
A recreational hobby that individuals or familes/small groups of people can participate in. It started in the middle of the 19th century in Dartmoor when in 1854 a Chagford guide called James Perrot set up the first letterbox at Cranmere Pool on North Dartmoor. Originally it was just a cairn (small pile of rocks), the idea was for a walker to leave a message there for the next walker to collect and so on. Later, other boxes were established at Taw Marsh (1894), Ducks Pool (1938), Fur Tor (1951), and Crow Tor (1962). These boxes are deep into the moor and still represent a challenge. People from all walks of life go letterboxing, they spread from Cornwall to Scotland, the U.S, Holland, Germany and New Zealand. The boxes hidden contain a visitor's book and rubber stamp. When finding the box an impression of the rubber stamp is taken using an inkpad and stamped onto either a book or postcard. The visitor then either signs the visitor's book, or use their own personal stamp to leave their mark.
Letterboxing is done without the use of a GPSr, but with a recent interest in combining geocaching with letterboxing the LETTERBOX HYBRID cache has evolved. Basically this means that the two are combined using both a GPSr (to a lesser or greater extent) and clues to find the cache.
The next feature that applies to letterboxing and hybrid letterboxing is the addition of a stamp to the box that isn't to be removed by the finder. When you find the cache, you stamp the "box stamp" onto a logbook that you may carry. I appreciate that not all geocachers carry a log book - that's not a problem. Then you stamp using your own stamp (again you may not carry a stamp, don't worry), your "trail name", and the date you found the cache into the logbook, as normal. In letterboxing people keep track of how many boxes they've found and how many boxes they've placed, just like in geocaching, but more likely in notebook form.
The given coordinates bring you to an information board near the carpark. Once here your GPS will be of very limited use to you 
To find the cache you will need to follow these steps;
1) Use the map on the information board to navigate your way to "The Shoreline Walk"
2) Enroute you will pass a green open area with a number of wooden benches (right hand side of path) There is a traditional cache here that you can pick up enroute
3) You will pass through two forks in the path, keep right at both, basicly follow the path along the lake.
4) Keep walking until you reach "204" (you'll understand when you get there)
5) Climb the small bank facing this, you will see a fallen tree to the left. You will find the cache under the top end of this. 5) You can either log your cacher name in the book in the normal way or leave your stamp (if you carry one)
6) The stamp in the cache is not a swapable, please do not remove it from the cache. Please return the cache in exactly the same manner in which you found it.
7) Finally I hope you enjoy your walk along the lake while doing this cache. As with all caches placed near out waterways exercise caution along the lake especially with younger cachers