It is possible to drive to the summit area using the access road beginning at R73439 76446 A.
This road is steep at the start so not one for a frosty day.The top is marked by a wide parking area with some seating next to a fenced off communications tower.
Extensive views of the whole Shannon region and Lough Derg.
Access is also possible by parking at R73560 78032 B and following the Lough Derg way uphill. Linkback: https://mountainviews.ie/summit/596/comment/5355/

Biggest problem I had with getting to the top of Tountinna was finding the road to take me up! While driving around, I came upon the Grave of the Leinstermen and the hill beside it on which stands Millenium Cross. If you are looking for a bit of a stroll, there is a carpark and a 1200metre walk over an established path to the cross. Met a couple of people out walking but it wasn't my cup of tea - is it just me or does anyone else find a large cross on a hill slightly un-nerving? It didn't help that one of the stay cables was snapped and the wind was whistling by the top of the cross, that and the old stone cross had been reduced to rubble by a lightning strike. Good views from the cross and probably not a bad spot for a stroll if you are bringing the kids.

Back into the car and eventually found the road up to Toutinna. First 100 yards or so are very steep but it's solid tarmac all the way up as it is obviously a service road for the communications towers that it houses. Ample parking space on top at the base of the largest set of towers. Unfortunately by the time I'd got up, it was starting to get dark (only got the one photograph) but there are some glorious views of Lough Derg to be had up there - I can only imagine the views on a clear, sunny day. Take time going back down the service road as there is a fantastic view back in the Ballina/Killaloe direction.

Now for the directions - I came from Ballina and the directions I got were as follows: imagine you are coming across the bridge from Killaloe - take a left at the mini-roundabout and then the next right up by the school. You then need to take the correct right turns to get up on top of the hill. This is where it all went hopelessley wrong for me so my directions are as follows:

From Portroe, follow the signs for Millenium Cross or Graves of the Leinstermen. Around 400-500 yards after the car-park for the cross (which should be on your right), the road swings to the right and there is road to the left (very sharp, nearly coming back on itself) down a hill. Go down this road and shortly after it swings right and starts to climb uphill, there is a road to the left. This is the service road. It's extremely steep in places, particularly the first 100 yards and I wouldn't recommend attempting it in icy conditions.. Linkback: https://mountainviews.ie/summit/596/comment/3351/

What views. The twelve pins way to the west and the wicklow mountains snowcapped to the east. This view rivals Ard Erins in the Slievebloom for expanse of countryside but Tountinna has Loughderg, shining blue on this clear day, 8th March 2010. I had to use the binoculars to be sure it was the Twelvepins and the Wicklow Mountains. Southwards The Galtees, Ballyhoura's, eastwards Keeper, the Devils Bit range from Knockanora to Benduff, way to the southeast the Knockmealdowns...and way to the south west barely visible the fabled Kerry Mountains....(I vow to return to get photo's). West wards the Slieve Bearna, Aughty's and the hills of Clare overlooking Galway bay (the bay may or may not be visble there was a slight ground mist). The great surprise was the Twelvepins and the Maumturks way way to the west. Northwards the Slieveblooms. Northeast along the Shannon - Shannonbridge Power Station to its left the seven sister woods of Eyrecourt. How to get there. I went into Ballina from the Birdhill direction. Go straight then take the first left along the loughderg drive. This road downgrades into a narrow country road but eventually it climbs to a viewing point, called the gravesof the Leinster men viewing point, near a telecoms mast. Opposite this mast there is a woodenpost with a hillwalker sign on it. The path appears to be recently dug. This route takes you all the way to the summit and those awe inspiring views. One point of interest more the trig is contained in a large plastic pipe but its not at the summit. The aerials are. Of course there is the service road... climbed today 28/3/10 with BigEoin, photo of Loughderg to prove it. NB The name of the hill on which stands the Millenium Cross and the ruins of the cross erected to celebrate the Eucharistic Conference in 1932 is Laghtea, it is 1,088 ft over sea level. I note that it is not listed on Mountainviews. While it is only a small height up from the road it is probably 500 ft over the lake at least, it is a maybe.....perhaps due to its great views it should be considered for inclusion! Linkback: https://mountainviews.ie/summit/596/comment/4487/

As mentioned by jackill, it is possible to drive all the way to the summit of Toutinna which is what we did given the summit was covered in cloud. I would imagine the other option mentioned by jackill from the North side of the hill going up by the Graves of the Leinster Men would be a little bit more satisfying than driving all the way to the summit. Linkback: https://mountainviews.ie/summit/596/comment/20196/