I don’t exactly know why, but this has been bothering me for about a week.  It has something to do with this article, I think.  Anyhow, just so you know…

• Sledge: British word for “sleigh,” also “a strong, heavy sled.”
• Sleigh: “an open usually horse-drawn vehicle with runners for use on snow or ice.”
• Sled: “a vehicle usually on runners for transportation especially on snow or ice; especially : a small steerable one used especially by children for coasting down snow-covered hills”

Okay, that’s actually not very helpful, Messrs Merriam and Webster.  Can dictionary.com be more helpful?

• Sledge: “a vehicle of various forms, mounted on runners and often drawn by draft animals, used for traveling or for conveying loads over snow, ice, rough ground, etc.; a sled; British a sleigh.”
• Sleigh: “a light vehicle on runners, usually open and generally horse-drawn, used esp. for transporting persons over snow or ice;  a sled.”
• Sled: “a small vehicle consisting of a platform mounted on runners for use in traveling over snow or ice; a sledge.”

So a sledge is a sleigh, a sleigh is a sled, and a sled is a sledge.  AWESOME.

What about just asking Meneer Google*?  We get, via blurtit.com:

The difference between a sledge and a sleigh all comes to down size and load.

In general, a sledge is smaller and used in the main for transporting goods. It is also able to travel over rougher ground than a sleigh.

The sleigh, meanwhile, is normally much larger than a sledge and is principally used for carrying people rather than goods. Due to their size sleighs are pulled by horses rather than dogs which are the normal means of propulsion for a sledge.

Can we trust an anonymous internet dude who goes by Wombat96?  Maybe…  Yahoo Answers UK user blackpool lass has what appears to be more in line with what dictionary.com suggested:

“hiya, its all the same thing,but people around the world call it by a different name.”

Seems pretty reasonable, really, and certainly more helpful than the other answer on the same page, which was simply “Nomenclature,” put forth by hopefully-but-inaccurately-named user “Captain Adequate.”

Finally, this dude just conducts a poll to get a nice, democratic answer:

It would seem that ‘sled’ has maintained itself as the usual word for such objects in North America, and ‘sledge’ in Britain, while ‘sleigh’ generally has narrower connotations everywhere, being specifically associated with Santa Claus, reindeers and that kind of thing. I doubt that the latter was so much the case fifty years ago; Fowler indeed speculated in the 1930’s that ‘sleigh’ would probably displace the other terms. Usage in Australia/NZ seems caught between British and American as so often.

That’s sounds pretty good to me.  Interestingly, the guy mentioned above was not just trying to satisfy some silly curiosity, but needed the advice for help translating old Dutch and German documents.  Noting that it sounds funny to him to have reindeer pulling a sled, he wonders:

Is it something in the sound of the two different words? So: ‘sledge’ it must be, not only because I am writing in English English but also because it sounds more fitting for me for the heavier vehicle.

This makes sense, I think, because it brings to mind a sledge hammer- a big heavy thing used for smashing concrete and whatnot.  Unlike the words in question, this “sl??” has it’s root in Old Norse.  Whew!  Google really does have plenty of discussion, but if you add it all up and divide it by whatever, I think the trinitarian viewpoint is the best.

*Meneer is apparently Dutch for “Mister,” and all these old school snowmobile words come from the same Middle Dutch word, sledde.  FWIW.

UPDATE:  Do these image searched help elucidate things?  Maybe, maybe not.

1. Sled
2. Sledge
3. Sleigh

They do seem to confirm that sleigh=Santa, if nothing more.