Climbed on Tuesday 07th June , 2 hrs 45min return. I went up the track from the road after the entrance to Cashel House Hotel and just before the church L80303 42385 A. Walked past the graveyard and through 2
gates to L80749 43076 B and walked around the base of the hill to the South Side I actually went too far south as it was not necessary , the southern side is more challenging . Great views of the Bens and Mamturks.
I did not return the same way and came all the way down the South side directly to the gardens of the Castle House Hotel. Before the Hotel grounds , I was delayed for 10 mins looking for a gate in order to avoid having the climb the stone wall. I would say it could be a very wet boggy walk in normal weather but the recent long dry weather made it easy on the foot. Linkback: https://mountainviews.ie/summit/947/comment/5706/

Parking at the church at L80303 42385 A you can pass through the gate to the left side of the church as you face it, up the slope. This boithrín leads to the graveyard at L80714 42976 C. The graveyard contains the easily discernible circular ditch of the original Caisel or Ringfort that gives the hill and townland its name. To the north of the graveyard through a gate is a maintained holy well. Passing the graveyard on your right hand side you can go through a gate onto open ground and the hill rises away to your left. The lower slopes are easily traversed being grassy but there's a decent rocky clamber to the top. Views are excellent in all directions with the full southern flank of the Bens laid out before you, Lissoughter and the Maams, Roundstone bog, Errisbeg, and the bays to the south, all beautifully arranged. This is also fantastic spot to watch a sunset over the lakes of Roundstone Bog or the Bens if you're properly equipped with torches for a descent in the late dusk.

For extra interest, though out of the way of the best route there is one of the surprisingly few megalithic sites in Connemara on the SE flank of the hill at L79279 43217 D, a wedge tomb, well preserved.

Cashel hill, could be taken in in a day including Errisbeg & Cnoc Mordáin as suggested finishing with a drink O'Dowd's of Roundstone maybe Linkback: https://mountainviews.ie/summit/947/comment/17975/

The church mentioned by liz050 is a good place to park for this hike or If you are pressed for time it's possible to drive to the graveyard. At the graveyard there is a gate that leads out to the open hillside. A short steep climb North West will take you to the summit of the hill. The views of the Maumturks and the Twelve Bens from here are second to none. A fantastic little gem of a hill. Linkback: https://mountainviews.ie/summit/947/comment/20106/

Follow the directions as detailed by the other contributors and once you are through both gates I would immediately continue on the ascent as the full impact of that remarkable Connemara vista will hit you full on. It's stunning. I've been there four times now and hope to do it again as for the life of me I cannot locate the Scrahallia Wedge Tomb which is located at the foot of Cashel Hill. Not the most challenging of hikes but trust me the scenery is striking. Linkback: https://mountainviews.ie/summit/947/comment/20322/