The Office of Strategic Services, the World War II-era agency that preceded the CIA and many special operations units, deployed teams into France for months starting just before D-Day. A map slide produced after the war showed just how insanely successful the 423 men assigned to the mission in France were.
(National Archives and Record Administration)
We've previously written about the "Jedburgh" teams, commandos from the U.S., Britain, France, and other countries who deployed into France to counter the Nazis. This mission officially kicked off June 5 as the teams jumped in just hours before the larger D-Day invasion.
These teams contained only two to four personnel each, but they partnered with local resistance forces and protected key infrastructure needed by the invading forces while also harassing or destroying German forces attempting to reinforce the defenses.
But the Jedburghs weren't the only Allied commandos on the ground. The OSS deployed 21 Operational Groups into France as well as two into Norway. These teams were supposed to contain four officers and 30 enlisted troops, though shortages of trained personnel led to many teams deploying at about half strength.
These original OGs operated as guerrilla bands, destroying German infrastructure and conducting ambushes and hit and run against Nazi formations. They deployed with their own medical support and were well trained in infantry tactics, guerrilla operations, demolition, airborne operations, and more.
These two forces, the OGs and the Jedburgh Teams, were the primary OSS muscle, providing 355 of the OSS's 423 men in France. As the map above shows, they deployed across France and inflicted almost 1,000 casualties against German forces and destroyed dozens of vehicles and bridges.
And the OGs were tightly partnered with the French Maquis, a partisan group that resisted the Nazis. The Maquis and OGs captured over 10,000 prisoners.
Not bad for a force with less than 500 members.
It's easy to see why the post-war government re-built the OSS capabilities. Even though the OSS was broken up, the modern military's special operations units, the CIA, and other teams now carry on the missions and legacy of the OSS, including the OGs and Jedburgh teams.