It seems when we discuss “haunting melodies” we most often talk about airs. There are jigs (as well as reels and marches) that have that “hauntingness” about them. Without rushing to set new land speed records (how many of you are actually playing for dancers now?), but even at a respectable pace, some jigs are mind blowingly haunting.
I’ll start off with “Brother Gildas’ Jig,” a tune I recently and happily rediscovered.
Any others of note?
Philo
I find “The Road To Lisdoonvarna” can be haunting if you start slow and work it up to speed later.
I will have to look up the tune you are talking about, could be another keeper!
Sandy
The Irish Washerwoman, the Kesh. 
I think pretty much any of the various Paddy Fahy jigs. And Garret Barry’s comes to mind.
Ghost of Ballybrolly
The Ghost that 'aunted Bunty
The Jenny Hoolet or Lizzie Mudie’s Ghost
The Haunted House jig
Loch Ness Monster
The Halloween Jig
Banshee’s Wail over the Mangle Pit
Lilting Banshee
I’m assuming this is what you meant by haunting.
Remember, when you ASSume,
you’r always right.
Just my oppinion.
I’d like to submit The Strayaway Child as the hauntingest jig.
The hag at the churn does it for me. Not haunting in the cosmic-drainpipe sense, but in more of an eldritch sense.
I still think slow reels make some of the prettiest tunes – I started a thread about that a couple of weeks ago.
How about a slip jig? I got a VERY clear mental image of skeletons dancing with jack 'o lanterns when I listened to Fig for a Kiss, so much that I can’t shake it out of my mind…ghostly dancing in a graveyard. . .complete with headstones and clouds skittering across the moon, rats peeking out of the shadows.
You probably mean hauntingly beautiful…:shrug:
Winnie Hayes’ is about the hauntingest i play regularly.
Martin Hayes’ first cd has some good ones, can’t seem to locate it right now…
Hey Ty, the dark thing works for me too…
Philo
the hauntingest jig I play if Gallaghers Frolics.
I’m not quite sure what everone means by haunting but for me one of the jigs that sort of “inhabits” me is Paddy Canny’s Caves of Kiltanon. Other worldy, in my opinion.
Carol
If a Slip Jig counts, then its The Butterfly for me.
I’ve always thought that the “haunting sound” comes from the minor keys and that tunes in the major keys are usually more brighter in mood.
Slan,
D.
I find “The Road To Lisdoonvarna” can be haunting if you start slow and work it up to speed later.
As “up to speed” is not available to a great many of us, did I say ‘me’? most any tune can be haunting. We just hope it don’t scares ya to death! 
I don’t get much mileage whenever I use that expression…
I’ll second “Strayaway Child”, particularly the flute version I’ve heard off of mp3.com (I don’t recall the artist), and “The Butterfly” as it is usually played.
Here’s a recording of Michael Gorman (the composer) playing “Strayaway Child”: here.
A somewhat lesser-known tune that is very melodic and haunting and usually played at those speeds is “The Lonesome Jig” (also known as “The Rolling Waves”).
– Scott
Thanks for that recording Scott - really beautiful tune. The Lonesome Jig (aka The Rolling Waves) is also a personal favorite.
Philo
The term “haunting” is quite subjective, but there are a ton of jigs that I’d consider haunting in one way or another…be it a minor key, overall feel of the tune, or accompanying chord structure that can make a tune sound very haunting. I agree with many of the posts, and here are just some others that I consider haunting in no particular order or preference. There are too many more to post.
E minor Jig
Tynah Jig (Delaney’s)
Coleraine
Austin Barrett’s (Dusty Windowsills)
Pat Burke’s (The Hills of Glenorchy)
Mr’s Martin’s Favourite
Lark in the Morning
The Blue Angel
Hillsboro Highlands Heat (Ann Hooper)
Carraroe Jig (depending on the accomapnying chord structure)
Humors of Trim (Rolling Wave)
Kilavel Jig
Mug of Brown Ale
Condon’s Frolics (Castletown Conners)
The Walk Around
The Smile of Nancy Barlow (more of an air)
Down the Back Lane
The Gaelic Club
The Tenpenny Bit
Drummond Castle
Paddy’s Leather Britches (powerfully haunting to me)
Huntingtone Castle
I Lost My Love
A Slow Slide
Bill Harte’s
Jump at the Sun
Mrs. Charles Graham’s Welcome Home
Robin’s Bodhran
DC
SlipJig Celtic Band
I play the “Jig in Em”. I got it orignally from an MP3 by Slua Si played on the pipes.
the Legacy Jig - Joannie Madden combines it with The Tar Road to Sligo on her “Song of the Irish Whistle” CD… I get visions of the pirates on the Black Pearl going about their deck scrubbing and such - the percussion stuff on that cut is excellent too.