Opening a weighty volume of yellowing paper, Sally Reeves gently unfolded a cloth drawing of an elaborate burial chamber at Metairie Cemetery.

The drawing, attached to an agreement to build the tomb, is one of hundreds of thousands of carefully preserved documents dating back to the 1730s that provide details of life in New Orleans throughout its history. And, whether for purposes of genealogical research, historical scholarship or simple curiosity, they’re all available for the public to peruse.

The documents are part of the Notarial Archives division of the Orleans Parish Clerk of Civil District Court’s Office, which is celebrating American Archives Month with tours of its collection at a Poydras Street office building.

The office houses about 5,000 pages of records from the French colonial era; 225,000 pages from when the colony was under Spanish rule; and hundreds of thousands more from later eras up to the present.

“When you’re entrusted with these records, part of your job is to let people know they exist and share this treasure with the public,” said Reeves, the collection’s archivist.

Anyone can browse through the collection and look at the original documents — bound in thick volumes — in a reading room open weekdays from 8:30 a.m. to 5 p.m.

The breadth of the archive is unique, thanks to Louisiana’s status as the only state operating under civil law inherited from the French and Spanish. The English common law system in the other 49 states uses notaries mainly to verify the identities of those signing documents, but civil law charged them to be archivists, as well.

Contracts, wills, marriage records and other legal documents had to be executed in front of a notary, who would keep the originals and bind them into volumes.

Unlike the records at civil court itself — a huge repository of often angry, bitter lawsuits — the Notarial Archive is filled with pacts and bargains. Reeves, who has served as archivist for more than four decades, likes it that way.

“Having lived with this since 1971, I think I have a very sanguine view on life because I deal only with amicable agreements,” she said.

It is also a historian’s dream: shipping lists, accounts of trouble at sea or on the river, the charters of benevolent societies and detailed architectural renderings of buildings and tombs to be constructed.

The archive is not just written documents. In fact, one of its most notable features may be the collection of 5,100 drawings that accompanied land sales. Reproductions of the yellow- and red-tinted maps are often used now as decorations.

The maps stem from a practice in the colonial period, when those looking to sell property would have to post a notice on the wall of the church to make sure that anyone who had a claim on the land knew a sale was imminent, Reeves said.

The notices also became a form of free advertising for the properties, which were usually sold at auction. To draw more interest in the sale, the notices became more and more elaborate, evolving from simple maps to basic drawings of the houses that were for sale and eventually into detailed renderings of the property, occasionally highlighted with bold headlines in circus-style fonts.

“Some of this could be in a museum, but it’s a living document still,” said Sombra Williams, who took a tour of the archive on Thursday.

Though the primary draw for many is likely the historical or genealogical value of the records, documents nearly a century old have proven useful in legal disputes, particularly over property lines.

Reeves recalled one man who came to the archive when he was in a dispute with the Sewerage & Water Board, which said it would require him to connect his property near Lake Pontchartrain to the board’s system unless he could prove the property existed before 1950. A look at a huge map of the area from 1920, which included the property, saved him the tens of thousands of dollars he would have had to pay.

The public is welcome to look through the documents, though they must do so in the office’s reading room.

While parts of the archive have been digitized for preservation and indexes to each of the historic volumes are available online, the documents themselves can be viewed only in person. There’s a financial reason for that, Reeves said: The archive is entirely supported through the fees it generates from making copies of the records and prints of drawings.

New documents are now digitized as they come in, and records dating back about 30 years are available through a paid service on the Clerk of Court’s Office website. About 50,000 new notarial acts are entered into the archive each year.

There are some gaps in the collection. Some of the early French colonial documents are not in the archive; instead, they are stored by the Louisiana State Museum at the U.S. Mint.

Laws required notaries to work out of brick buildings with tile roofs to protect the records from fires, but some of the documents bear scars from various disasters.

Reeves noted singes on one book that was saved from a fire. Other records, from the 1950s, had not yet been moved into the Poydras Street office when Hurricane Katrina struck; they were in a basement that flooded during the storm and had to be freeze-dried to be preserved.

For a visitor like Williams, the documents are living proof of the city’s long history.

“You know New Orleans has a rich culture and a rich history, but to know there’s a place that has documentation of that, that’s fascinating to me,” Williams said.

The next tours will be held Thursday and Oct. 29 at the office on the third floor of 1340 Poydras St. Because space is limited, those wishing to take the tour should register in advance by emailing jstrawn@orleanscdc.com.

Follow Jeff Adelson on Twitter, @jadelson.