Before the directive, 99 of the 136 posts in the U.S. had allowed visitors to enter unchecked, according to a report by The Associated Press.
Army officials say the checkpoints are solely for monitoring people coming into the establishment, and they are not intended to keep civilians out.
"We want to ensure we know who’s coming to visit us," Army spokesperson Maj. Chris Conway told The AP.
Security measures will vary from base to base. At The U.S. Military Academy at West Point, N.Y., for example, there are no plans to increase already stringent security.
Some bases already implementing the new security measures are Fort Stewart in Georgia and Fort Bragg in North Carolina.
"It should have been done a long time ago," Army retiree Robert Harvey told The AP. "There’s just too much access."