You could approach Seefingan from an alternative route to Seefin, but why would you want to? Seefin Hill ought to be your first stop if you're heading this way. From Seefin Hill passage tomb the distance across to the cairn on Seefingan looks deceptively short. Don't be fooled: it's quite a hike. And whereas the ascent to Seefin is relatively dry, the dip and the ascent across to Seefingan was boggy the day I was there on the last day of May 2006.
My anticipation at what I was going to encounter on Seefingan was heightened as I approached and saw the cairn up close for the first time. It's slightly larger that the tomb on Seefin and I thought that there must be a passage and a chamber, but sadly no, there isn't. It's still impressive, with amazing views across the city towards Howth. So what was it's purpose? (Pure speculation warning) Sitting there atop the hill it seemed to mirror Howth peninsula way in the distance, as if its builders were paying homage. Others have noticed the significance of Howth before and in my travels around some of the other sites near here I have tended to agree.
I had a very short time up here as light was fading fast and I didn't want to be caught heading down the mountain in the dark. There is an indentation on the east side of the cairn that looks like it could have been a passage entrance, though I guess this is just wishful thinking. There are quite a few quartz boulders peppered about the cairn surface and below. The modern pillar stone atop the cairn was quite strange and could signify the limit of the army rifle range that is in the valley below. (On the day I went up I could hear firing, so be warned). Overall, a bit of a disappointment, especially after Seefin, but worth the extra slog nonetheless.
There are 3 hills around here with megalithic significance. I met some hill-walkers and they were on a tour of the 3: Seahan (648 metres), Seefingan (724 m) and Seefin (621m). If you had an afternoon and were feeling energetic, this could be an ideal way to work off some pounds. (If you start at Seahan you would need to take in Corrig mountain (618 m) on your way across to Seefingan.)