Packwood, who has figured just once for the Blues first team so far this season, is currently on loan at Cheltenham Town. He will be looking to add to his single U23 cap for his country.
The training camp is being held from 23 March – April 1 and will be staged in two locations - Sarajevo and Copenhagen.
As part of the camp, Andreas Herzog's United States side will play the Bosnia & Herzegovina U23 national team on 27 March 27 and the Denmark U23 national team on 31 March.
This camp is part of the United States' preparations for 2016 CONCACAF Olympic qualifying to be held in October 2015.