The 6/8 march is sometimes confused with the jig simply because it is in compound time. The 6/8 march is usually played quite a bit slower than the jig and with a more dotted rhythms, i.e.,

The pipe band can also be seen marching along to these tunes. An easy way to identify these tunes as being in 6/8 is to try to distinguish how many quavers are in each group. In the 6/8 march there are 3 quavers in each group:

whereas, in the 4/4 march there are 2 quavers in each group:

Try tapping out the rhythms of the 6/8 march then the rhythms of the 4/4 march to feel the difference for yourself.
Some famous 6/8 marches include Farewell to the Creeks, (a tune used by Hamish Henderson during the second World War for a song he wrote called The 71st Highland Division's Farwell to Sicily), The Bonawe Highlanders, Pipe Major Donald Maclean of Lewis and MacNeils of Ugadale.
Farewell to the Creeks
This is a very well known 6/8 march in the Scottish repertoire. Although principally
a bagpipe tune it is played on all instruments, often accompanied and in traditional
groups of all styles. The 6/8 march is particularly good to march to as the
dotted quaver usually appears on the beat giving the tune a great “lift”
or "swing". This also helps to keep the beat steady, important for
marching in the pipe band for instance.
The tune - like many 6/8 pipe marches - has 4 parts of 8 bars each. Each part is also repeated. So the form is:
A A B B C C D D
However, musicians will usually refer simply to each part by number (part 1, and so on). There is a lot of repetition in this tune. The first 2 bars of each part are repeated as bars 5 & 6. Also the last 2 bars of each part are the same.
Farewell to the Creeks was written by Pipe Major James Robertson.
Listen to a recording of Farewell to the Creeks and follow the score as you do.