The obvious way to climb Dart is from the road at H5894 9691 A, where there is a limited amount of parking. This point is at around 438m on the crest of a road that goes across the Sperrins. The walk to Dart is around 1.4k over rough heather and coarse grass.
Another way to reach Dart is from Sawel which is nearly 2k to the east.
The northern side of Dart has some crags. Views from the summit are substantial though Sawel is in the way to the east.
Dart has a cairn on the summit Linkback: https://mountainviews.ie/summit/244/comment/5004/

If you can arrange two cars, traversing Dart-Sawel can be a pleasant afternoon's walk. There is room to park a couple of cars directly to the west of Dart at grid ref 590970 B and also to the East of Sawel at 639975 C. The approach to Dart from the west is about the most interesting and easiest terrain you will find in the Eastern Sperrins - rocky with short grass mostly, with the Dart summit having the honour of being one of the only mountains in the range to be marked by a cairn (see pic). While many of the Sperrins have a Wicklow-ish roundness to them, Dart Mt has something approaching a defined summit. Enjoyable walk, from west to east, car to car taking about 3 hours , and that was at a leisurely pace. Linkback: https://mountainviews.ie/summit/244/comment/3394/

http://youtu.be/4GvIMiEx408

Dart is invariably tied at the hip with its bigger sibling (Sawel) and the join between the two is a defining feature in views of the Sperrins. Sawel has the kudos of highest and two county tops - somewhat greedy perhaps in taking the attention from those who may venture this way. All I can say is that they are at their best when experienced together.
Start at Sperrin Heritage Centre carpark ( 607936 D ), turn right and follow road along Genelly Valley for 10 minutes until come to a lane on the right ( 597933 E ) with a dead end sign. Climb up this lane and views quickly open out over the southern side of the valley.

As it levels out at around 300m the mountains of the northern side come into view, with the parallel road to Dart Pass below ,across Oughtboy Burn. Cross gate and strike off right onto open hillside for the shoulder of Dart. The climb is by way of a couple of steps between level areas before the short climb over rockier ground to the summit cairn, reached in 1h 20 mins.

There is a great view in all directions but especially west to Mullaghclogha and its steep slopes. Head north east with a short drop down into a broad col - with 1 km before the climb up the large bulk of Sawel, following the fence for short while but continuing straight when it veers off right.

The climb up Sawel is straight forward and on reaching the trig point the view west to the remainder of the range comes into sight. There is a long but gentle drop down from the summit to the road at Sawel Pass. The going all along was firm due to the recent dry spell but it would be a different story under normal conditions.

Turn right and follow the road down into the hamlet of Sperrin and then it is around 3 km back along the main road to the carpark. In all took around 4.5 hours and did i meet anyone else ? NO but i did see some bootprints! Can also climb from the direction of Sawel - see for a different approach. Linkback: https://mountainviews.ie/summit/244/comment/976/

Having had a rather late start (avoid going through Cookstown on a Saturday, the traffic is a nightmare), I chose the easy option: park the car at the pass on the road to Park at H58950 96912 F, and follow the fence east to the summit of Dart Mountain. There's room for three or four cars here by the cattle grid, and you'll be up at the summit in half an hour if you don't dally. Unfortunately the clouds came down as I started my ascent, so I only got a taster of the views. Linkback: https://mountainviews.ie/summit/244/comment/3599/

Like many other people, I combined Dart with its slightly higher neighbour, Sawel, the two tops being on my wish list ever since an abortive attempt last year. After reaching the latter's summit from the usual approach from the east (see entry on that page), I crossed over the fence close to the trig point and headed down towards the broad ridge joining the two mountains. As I said before I had naively imagined a small drop and narrow col when in fact it's quite a steep drop and a wide col. This made the thought of climbing Dart a bit more daunting but I decided to go for it anyway (I originally thought it would be a simple case of dropping down, taking a leisurely stroll along the narrow ridge, up a little bit to Dart, down again the same way, up a little bit to Sawel then all the way down the other side to where I started... all in 40 mins or so!).

I ran a good bit of the way down, which probably wasn't a good idea as I ended up on my back facing the wrong direction, with my dog running over to see was I ok! The view on the descent and rise is an interesting one, different from ascending Sawel: for one thing Dart has a more distinctive, craggier peak. Like Sawel it's rather boggy in parts and called for a few jumps. Towards the top I followed the line of the same fence, which I realized I probably could've followed the whole way, but I had fancied a straight drop and rise, peak to peak. There is a small cairn at the summit with views somewhat similar to Sawel e.g. Binevenagh, Lough Foyle and Inishowen to the north, although here there were better views west towards Mullaghclogha. I was able to pick out the minor road running north from the tiny village of Cranagh towards Park (Co. Derry), and slightly to the east, the forest track that others have mentioned. Once again, I crossed the fence and headed towards the track. The were some dramatic views on the way down this west side of the mountain, and a nice view down towards Cranagh with its pretty yellowish chapel. It started to rain and I hurried across sometimes awkward terrain before finally meeting up with the track (again I had to cross the fence, and again realized I could've followed it down). From here it was a gentle walk down towards the B47 Glenelly Rd, just east of Cranagh. I would recommend taking two cars if possible, as others have said, and parking them east of Sawel and west of Dart. Alll in all this circular route, while certainly an enjoyable day's hiking, is very long and requires a lot of road walking; the B47 is pretty busy. Linkback: https://mountainviews.ie/summit/244/comment/3848/

A montage of the view from west of Dart, looking eastwards to the highest Sperrin, Sawel. Linkback: https://mountainviews.ie/summit/244/comment/3400/