The Royal Welsh Regiment has been granted the freedom of Blaenau Gwent.
The county council opted to award the freedom scroll as a mark of thanks for soldiers' "heroism and duty in service".
Members of 2nd Battalion paraded behind a marching band through Ebbw Vale later.
Major Nigel Crewe Read, C Company commanding officer, said it was a "unique honour".
2nd Battalion has deployed companies to Afghanistan since 2009 and B Company is due to return home at the end of February.
Soldiers from C Company, which completed a tour of duty in Afghanistan between February and August 2009, took part in the parade.
Major Crewe Read said: "Even though we are just one company in a three-battalion regiment, we are accepting this honour on behalf of the whole regiment.
"The Royal Welsh has incredibly strong links to south Wales and to be granted the freedom of a borough that traditionally has such strong links to the Welsh infantry is a unique honour.
"It's very kind of Blaenau Gwent to let us parade through their streets."
The regiment has had three fatalities in all its operational tours in Afghanistan and Major Crewe Read said some troops had endured injuries that would change their lives forever.
"Their sacrifice is at the forefront of our minds."
The mayor of Blaenau Gwent, Brian Thomas, will officially present the freedom scroll to the Royal Welsh before they start their march through the town.
Des Hillman, the leader of Blaenau Gwent council, said: "I am proud that the council has pledged its full support to bestowing the freedom of the county borough on the Royal Welsh in honour of the brave men and women who serve in our armed forces every day - many of them, of course, from Blaenau Gwent."