Q-Ball wrote:...but the corps in the region attacked DOES, correct?
This would mean in a battle that some troops gain a bonus from the entrenchment, and some don't.
Yes, there are potentially 4 groups involved in a MTSG engagement. The defenders in province, the attackers in province, and then whatever is drawn in on both sides. On the assumption that the 'defenders' are in a defensive mode, and have had time to build entrenchments, that force will count as entrenched. Any units who move to support will not be entrenched.