US officials thanked the grand-niece of the serviceman who took the paintings following the allied invasion of Germany, who they said researched where the paintings came from after inheriting them.
Three of the paintings by local artist Heinrich Buerkel are each worth some $50,000, while seven others are valued at some $4,000 each. The painting by artist Alois Broch is worth around $10,000.
"Without the integrity and good will of Beth Ann McFadden, the repatriation of these paintings to the Pirmasens Museum could not have taken place," said New York southern district attorney Preet Bharara in a statement.
"Each work of art returned symbolises an act of justice, bringing us one step closer to the goal of repatriating all of the surviving pieces taken from museums during World War II."
The city of Pirmasens, heavily bombed by allied forces due to its position as a key manufacturing base, hid 40 of its museum's prized paintings under a local school building, but the works suffered heavy looting.
Ms McFadden's great uncle, US Army sergeant Harry Gursky, was stationed in Pirmasens after the fall of Nazi Germany.
Upon inheriting the paintings Ms McFadden sought to find out more of their history - eventually finding the US Immigration and Customs Enforcement had an open investigation searching for them.
ICE, the largest investigative unit in the Department of Homeland Security, has returned some 2,100 stolen art and antiquities to more than 15 countries since 2003.
"There are still dozens of these paintings missing from Pirmasens," said ICE Special Agent James Hayes.