Do not climb Slieve Maan for the views - there aren't any. Coniferous trees cover much of the mountain though there is a substantial ride along the line of the ridge near the summit. There are in fact two summits according to the Ordnance Survey and the SW summit has been determined as the higher. Initial access is via the Wicklow Way, mostly on forest tracks, either from the bottom of the Glenmalure valley at T 10379 90517 A or from the col on the Military Road at T 08757 87599 B. Either follow the Wicklow Way uphill from Glenmalure or downhill from the col on the Military Road. Go to T08482 88198 C. Head west around 170m until you find a ride. Go down this SW for 250m to find a small cairn which is the top.
Following a differential GPS measurement in 2013, the SW top at around T082 880 D was found to be around 1.68m higher than the NE one at an elevation of 547.82 Linkback: https://mountainviews.ie/summit/360/comment/5119/

Well we finally got to it. A glance through the comments will show that the twin summits of Maan have caused debate on the site for some years now.
Simon and I got around to surveying both of them in November 2013.
The results are interesting on two counts.
Neither summit made 550 meters and the highest is not that shown on the map up to this point by MountainViews.
We measured the North east top (MV current summit) at 546.134 meters.
We measured the South west top at 547.819 meters.

So the summit location changes. Linkback: https://mountainviews.ie/summit/360/comment/15258/

Although close, previously when walking the Wicklow Way, I had not actually been to the top of this hill. As it was one of two 500m tops in Wicklow that I had not climbed I decided to do so on 13 Sept. 2013. To say I found it uninspiring would be an understatement. However in the interests of anyone who wishes to climb Slieve Maan I thought the following comments might be helpful. I started from the forest entrance on the col below Croaghanmoira, parking at T0875087601 E and followed the track W into the forest. At the road I had noticed that the Wicklow Way which followed this route was re-directed N down the Military Road and not into the forest. A short way in I came across a sign which explained the re-routing, access was restricted beyond that point to authorised personnel. Fortunately for me some men were working there and as no forestry operations were being carried out that morning they agreed that I could continue my walk. However they also advised that due to the track closure walkers should use the next forest entrance signed for the Drumgoff Recreational Area at T094889 F some 2km further NE down the Military Road. Continuing on, with permission, I sought out the overgrown forest break at T0860088518 G and must agree that overgrown is certainly a very apt description. Indeed if it were not for some evidence of foot fall on the bank up into the forest one could be excused for missing it. My thanks are due to mcrtchly for pointing the way. From here I headed up NW twisting and weaving my way through the moss covered trees for some 300 metres to emerge out on to quite a large clear grass and peat hagged area with the the NE Top clearly identified by an old cairn at T0839588733 H, the MV listed high point for the hill, and close to a small pond. Once back down at the track, I decided to seek out the SW top at T082880 D. Though ill-defined it is located on a long narrow grassy area near to the line of an old fence and is even less interesting than it's twin some 800 metres to the NNE. While much of the forest below the SW Top has been harvested the top area is still surrounded by trees. My route was initially along a very rough vehicle track which led me up the side of the cleared hillside before I left it and went up through the trees to the top. From there I descended down E out onto the cleared hillside and back down to my outward track. In all this short detour added about 500 metres to a walk of 4.5km. Linkback: https://mountainviews.ie/summit/360/comment/15186/

This mountain's summit is part of a long ridge going SW-NE. You can get near to it using a track that leads NW from the Wicklow Way through the trees. Reaching the top of the ridge of this track you turn right and walk through some trees for around 150m to reach the summit. (OK -- this is easiest with a GPS). As of 2003 the trees were relatively open. The summit is marked with a small cairn and has a number of boggy ponds. There is another top marked for Slieve Maan about 800m north. The height for this is also given at 550 m on the map. We have selected the more southerly one as the summit because that's what the OS map says and the older 1/2 inch maps also say it is the highest (at a height of 1800 as opposed to 1797 feet). The photo shows the cairn and its surrounds. Linkback: https://mountainviews.ie/summit/360/comment/438/

This picture shows the views over to Ballycurragh Hill from the southern slopes of Slieve Maan. There's a forest ride that runs NE from the north west corner of the cleared area on the southern side of Slieve Maan, which leads you past both 550m summits. It's shown on the Healy map, but Sheet 62 doesn't go into this sort of detail. Linkback: https://mountainviews.ie/summit/360/comment/738/

I know that MountainViews has given its preference to the SW top of Slieve Maan rather than to the NE one, of roughly the same height. The OS map and, correspondingly, the Healy Glendalough/Glenmalure maps have led the way in this regard. Just for the sake of completion, however, let me add a photo of the less favoured NE "top". In reality it is simply a pile of stones in a flat forest clearing. I would have had difficulty finding it had it not been for the SMC contour map on my GPS, which for some reason has chosen to indicate the NE top as the principal one. Although the forest ride that runs parallel to the two tops is a pleasant walk, the encroaching afforestation limits the views considerably. (On the nearby Carrickashane Mountain, the problem becomes even more oppressive.) I was agreeably surprised, though, to see the familiar white triangle of the Great Sugarloaf exactly in line with the ride as I followed the track in its north-eastward direction. Linkback: https://mountainviews.ie/summit/360/comment/2770/