Mississippi’s largest National Guard base has been bustling with activity since it was federally mobilized to prepare soldiers for the wars in Iraq and Afghanistan. There’s no sign of letting up.

Hundreds of troops in the South Carolina National Guard’s 218th Brigade Combat Team are wrapping up a three-month training regimen at Camp Shelby, located south of Hattiesburg.

When the Newberry, S.C.-based 218th heads for Afghanistan, it will be the largest single unit deployment in the history of that state’s National Guard, said Chief Warrant Officer Tripp Hutto, a South Carolina Guard spokesman.

The troops will leave for Afghanistan soon after a send-off bash April 21.

Lt. Col. Doril Sanders, a Camp Shelby spokesman, said the roughly 1,800 South Carolina soldiers will get a week of leave beginning next week. They’ll return to the south Mississippi base April 19 to make final arrangements before they ship out.

The soldiers will assume command of Coalition Joint Task Force Phoenix and are tasked with training the Afghan National Army and the Afghan National Police, Hutto said.

This will be the second deployment for many of the soldiers.

“There are people that volunteered with the 218th just to deploy again,” Hutto said. “Some have been to Iraq and some and have been to Afghanistan.”

Military leaders are planning a concert April 20 for the troops and more than 3,000 family members, friends and dignitaries are expected to attend the April 21 deployment ceremony.

The departure of the 218th doesn’t mean trainers on the 136,000-acre facility near Hattiesburg will get a breather.

The North Carolina National Guard’s 30th Brigade Combat Team is scheduled to begin arriving this weekend for their annual training, Sanders said.

The unit won’t be deploying overseas, said Sgt. Kathryn Jarvis, a North Carolina Guard spokeswoman.

It’s not uncommon for other states to send their troops to Camp Shelby for two-week annual drills. The base can accommodate thousands of soldiers.

Other units that have passed through the base before being sent to the Middle East are also returning for more training. Mississippi’s 155th Brigade Combat Team and Tennessee’s 278th Regimental Combat Team, each made up of more than 3,000 soldiers, will conduct their annual training this summer, Sanders said.

Both the 155th and the 278th trained at Camp Shelby before spending nearly a year in Iraq. This time they’re just brushing up on their skills, not preparing for an imminent mission, Sanders said.

More than 40,000 Guard soldiers from dozens of states have trained at Camp Shelby since June 2004.

“They come to Shelby mainly because of the training facilities and the type of training — theater immersion — that is being offered,” Sanders said. “The soldiers are performing well. They train like they are going to fight.”

Theater immersion training uses Arabic role-players, simulated battlefields and mock Middle Eastern cities to mimic the sights and sounds the troops will meet with overseas.

The training program is tailored to replicate the types of conflicts the military is involved in and is routinely updated to parallel changes on the battlefield, officials said.