It's not easy to describe exactly how to get here through the variety of lanes. Probably best to get an OS map. Or try this. On the B3297 just north of Helston, take the first left after the golf course (signposted 'Coverack Bridges'; and others). Pass the red phone box at Coverack Bridges and continue along the lane, past the school. Take the next right at a small triangular junction. This lane takes you past the farm at Chyreen. Just past Halvance Farm there is a small junction. Go right (signposted 'Releath' and the sexy menhir is then clearly in view on your right.
This slim but tall stone lies in the field wall on the roadside. There is space almost opposite to park for a short while.
Now there's a thing - I never knew what this was called! Didn't really know where it was! We were just driving around trying to find stones and things on a really lame map of ours! On the way back from a really soggy day at Goonhilly - nearly drove past it, actually! It is (as I recall - it was nearly 2 years ago now...) just past the corner on the road from Tregathenan to Releath pretty much embedded in a hedge, but by 'eck - what a corker! Looking at the picture again, I realise that it was not embedded in a hedge at all. Silly boy.
Mentioned by Craig Weatherhill, in “Cornovia: Ancient Sites of Cornwall & Scilly” (Cornwall Books - 1985, revised 1997 & 2000) as a “fine stone…situated just below the summit of Prospidnick Hill, on the east side of the lane, and stands 3.0m high. Like so many other Bronze Age menhirs, it is known locally as ‘The Longstone’.”