Q:

Height of the LoTR Races

Is the height of races (men, elves, orcs, goblins, etc) ever mentioned by Tolkien? If not, did the movies just make up the certain heights?

A:

Yes, he has, but as far as I remember, not for all the races. 

Hobbits were 3 to 4 feet tall  -- average 3 feet, 6 inches ( Letter #27)

Actual size – only important if other objects are in picture – say about three feet or three feet six inches. 
Source

Orcs were 3 & 1/2 to 4 feet tall ( The Fellowship of the Ring)

The size of the Elves and the men was similar. There was a mention I think that the dwarves had similar height to the Hobbits, if not slightly taller.

