The letters, along with thousands of maps, documents, photographs, and books, fill cabinets and shelves inside a room-size vault at the Camden County Historical Society in the 1900 block of Park Boulevard in Camden.
They're rarely, if ever, exhibited - especially now, while parts of the building complex undergo restoration following water damage caused by broken pipes during last winter's severe cold.
But the vault was not affected, and these treasures of history - including fabric stained by Lincoln's blood following his assassination, a piece of Martha Washington's gown, postcards by the poet Walt Whitman to a friend in 1881, and early maps of Camden - are available to researchers upon request.
"Most people don't know what we have," said Jason Allen, the society's executive director. The vault's contents are "valuable and important," he added.
"There's power in holding the documents; they radiate power," he said. "The letter Lincoln wrote, and the cloth stained with his blood, are almost sacred. . . . They matter in this digital age."
People - especially young people - have grown accustomed to "living in a virtual world, and don't connect to documents," Allen said.
"Having digital copies allows us to see more but interact less," he said. "Digital devalues things we do have access to."
Many of the documents, books, and relics were donated by Charles Boyer of Camden County, who endowed the institution. Others came from members of the public.
The framed fabric with Lincoln's blood is accompanied by a description: "This small piece of linen was on April 15, 1865, soaked with the life blood of the murdered Lincoln at Ford's Theater, Washington D.C."
The blue and white piece of Martha Washington's gown was "worn at a dance in Fredericksburg, Va., the night before her husband left for battle," according to its description.
And in another frame is a "piece of wood from the White House in the room where President Lincoln signed the Emancipation Proclamation."
"People back then were looking for souvenirs," said William Roulett, director of interpretation and education at the society.
Other items, though, were handed down over the past couple of centuries as part of the public record.
One was a handwritten deed for land being transferred from Thomas Wharton to William Cooper in 1814, which referred to the area as the Town of Camden. This was one of the first written references to the name of the city, which was not officially incorporated as Camden until 1828.
"Every time I come in here, I find something interesting," Roulett said in the vault.
"Why would Camden be chosen as the name of the city? Lord Camden was in the House of Lords in England," he said. "But he was supportive of the colonies."
One visitor who came to "research the Fourth Amendment and the Founding Fathers' original intentions involving search and seizure was fascinated" by the Camden reference in the deed, Roulett said.
"These documents are significant. They're [in the vault] so they can be protected and preserved," he said.
A parchment map - produced by John Clement Jr. in 1846 - showed Camden County as then being made up of Gloucester, Winslow, Washington, Delaware, Newton, and Union Townships.
Nearby, in the foyer of the society's building, is the displayed uniform of Clement's father, John Sr., who served as a paymaster during the War of 1812.
The vault also holds an 1870 map titled "Plan of City of Camden," showing the layout of the town.
"This is why the streets are the way they are - and now we're stuck with them," said Leonard Irwin, a society volunteer and retired art and English teacher who lives in Waterford Township.
"There was no famous battle here," he said. "People lived and died, and you see trends over time."
Three days a week, Irwin organizes, restores, and encapsulates maps and other documents as part of preservation efforts. "Some can't bear handling," he said.
And some probably haven't been handled for more than a century.
"It's kind of special when you open a Bible from the 1700s and wonder about the last time light hit that page," Irwin said.
The historical society's Charles S. Boyer Building, housing the Richard Hineline Library and administrative offices, is open by appointment only, Wednesday through Friday.
The other parts of the complex - the Camden County Museum and Pomona Hall, an 18th-century plantation house - are temporarily closed to fix January water damage that followed the breakdown of an old heating system. It's not clear when the work will be completed.
For more information, call the Camden County Historical Society at 856-964-3333.