The town takes its name from the ruined castle, built in 1210 by the Knights Templar under the leadership of Richard Earl de Clare, more commonly known as Strongbow.
And in the centuries that followed, the castle and lands changed hands many times, with Walter Raleigh and Richard Boyle, the first Earl of Cork, among its owners.
The castle lands now comprise the five star Castlemartyr Resort, complete with its own top class golf course.
The most popular resident though is a more recent arrival, none other than a certain Mr. Patrick Shortt of Killinaskully fame. And you will get more than a jumbo breakfast role in his very fine riverside pub.
The cache is a small plastic container, placed across the river from the pub.