St. Louis Cemetery No. 1, established by Spanish royal decree on August 14, 1789, is the oldest existing cemetery in New Orleans. It was built to replace St. Peter Street Cemetery, which had long been overcrowded. The cemetery was once significantly larger than its current-day footprint of one square city block. Due to heavy use throughout its early years, the cemetery expanded from the confines of its original boundaries, eventually reaching directly up to what today are the east-bound lanes of Rampart Street; the subsequent construction of Basin Street reclaimed this portion. In addition, within the early period, the cemetery also covered about one third of the upriver block bordered today by Conti, Basin, Bienville, and Tremé Streets. Prior to 1852, it also reached beyond the confines of where St. Louis Street currently borders the cemetery. The largest area of the retracted footprint is where the cemetery extended in the rear to accommodate sections for Protestants, and those of African descent. When Tremé Street was extended in the 1830s, the majority of the Protestant remains were moved to the Girod Street Cemetery, which was deconsecrated in 1957. Today, St. Louis No. 1 is bordered by Basin, St. Louis, Conti, and Tremé Streets, and only a small strip of the Protestant section remains bordering Tremé and Conti Streets. The cemetery block is bordered on two sides by brick wall vaults. The unusual character of the tombs, the legends surrounding the historical figures who occupy them, and the aura of Louisiana’s fascinating past make this the best-known cemetery in New Orleans.

Due to the city's swampy soil, underground burials were quickly found to be impractical. The practice of above-ground tombs was introduced by French and Spanish colonists, continuing a long tradition both in Europe and in other colonies. The early tombs were made of brick, usually plastered and limewashed in a variety of colors. There is a large variation of brick tomb styles, and although mostly modest in design, they are functional, practical, and aesthetically pleasing. Because tombs were usually designed with one or more crypts, it was common for families to use the same tombs for several generations, thus maximizing the valuable and scarce burial property.

In the early 19th century, marble became popular as a building material. Elegant marble tombs were locally designed and built along with the more modest brick monuments. These tombs were often enhanced with freestanding marble figures and urns, as well as relief details such as those found on inscription plaques.

These architectural monuments serve to memorialize many people important to the historical development of New Orleans, the Louisiana territory, and the United States. Here lie the remains of colonists, soldiers, artists, poets, historians, aristocrats, politicians, and diplomats–as well as everyday people–and their descendants.

St. Louis Cemetery No. 1 was listed on the National Register of Historic Places in 1975, and was added to the African American Heritage Trail by the State of Louisiana in 2008.

Consecrated in August 1823, St. Louis Cemetery No. 2 is the second oldest surviving cemetery in New Orleans. It was established in an effort to prevent the spread of diseases, such as cholera and yellow fever, by moving burials away from the populated center of the city. Early city maps show the cemetery as one continuous piece of property running from Canal Street to St. Louis Street. Iberville, Bienville, and Conti Streets were cut through in 1847, dividing the cemetery into four squares. However, the square between Canal and Iberville was never fully used as a cemetery plot and was eventually sold, leaving the three squares as they exist today.

The cemetery is filled with a variety of above-ground tombs made of various combinations of brick, marble, and granite, reflecting both traditional and contemporary tastes and styles. The ironwork fences, gates, and crosses include some of the finest examples in the country, with approximately twenty-five varieties of cast iron and many wrought-iron enclosures. Along with the traditional brick monuments, impressive granite and marble tombs are built in the neoclassical, neo-Gothic, and Egyptian Revival styles, many of which were designed by noted local architect J.N.B. de Pouilly. These tombs line the avenues and walkways within the cemetery walls, creating a unique appearance that sets New Orleans cemeteries apart. Many of the tombs resemble small houses, leading some to describe the cemetery, and others like it, as "Cities of the Dead".

St. Louis Cemetery No. 2 was listed on the National Register of Historic Places in 1975, and was added to the African American Heritage Trail by the State of Louisiana in 2008. Square 3, between Bienville and Iberville streets, is considered the largest collection of outdoor monuments to African Americans in the United States. (See the NAACP guide to St. Louis No. 2 in Additional Resources.)

The cemeteries of New Orleans are among the most significant monuments to its culture and history. They house the earthly remains of the city's inhabitants dating back to the end the 18th century, those of the wealthy and the poor, the enslaved and the free, the immigrant and the native. Moreover, the tombs themselves constitute an essential part of the city's architectural patrimony, reflecting as they do the cultural debt that New Orleans owes to the traditions of France and Spain, the physical realities of the unforgiving south Louisiana environment, and the artistic genius of some of the city's most talented architects, sculptors, and craftsmen.

The cemeteries have long been considered among New Orleans's most noteworthy attractions. For nearly as long as there have been tourists in New Orleans, they have been drawn to its "Cities of the Dead." Already by the late 19th century, it was common for guidebooks of the city to include descriptions of the picturesque appearance of its oldest cemeteries, and some of the earliest postcards of the city featured images of them. Earlier, in the mid-19th century, descriptions of the cemeteries were being published in serial publications like Harper's Weekly, and also in books—read all over the world—by authors such as Mark Twain and Frederika Bremer. Earlier still, in the first two decades of the 19th century, the cemeteries of New Orleans attracted the attention of visitors to the city who wrote about them in their journals and letters home. These early New Orleans cemetery visitors include Benjamin Henry Boneval Latrobe, the father of the architectural profession in America, who wrote about his visit to New Orleans's oldest cemetery, St. Louis No.1, in 1819, and the visitor John Pintard, who had described the same site in 1801.

The picturesque qualities of the cemeteries, although long cherished by visitors, are indicative of their deterioration. Due to their constant exposure to the elements, the sensitivity of their predominant materials (marble, local soft brick, wrought and cast iron), their susceptibility to theft and vandalism, and other factors, the long-term sustainability of New Orleans's historic cemeteries is far from guaranteed. The protection and conservation of the cemeteries has been of paramount importance to concerned citizens since the city's preservation movement—one of the very earliest in the country—got its start in the first quarter of the 20th century. Alongside other such seminal organizations, the Society for the Preservation of Ancient Tombs was founded in 1923. Its first (honorary) president, well-known writer and historian Grace King, helped turn the public's attention to the cemeteries' plight, although the society eventually lost momentum. In the late 1930s the Works Progress Administration transcribed the inscriptions at many of the oldest sites.

General L. Kemper Williams, founder of The Historic New Orleans Collection (THNOC) and an important early preservationist in the city, was involved with efforts to save New Orleans’s first Anglican burial ground, Girod Cemetery, founded in 1822. These efforts eventually failed, and in 1957 Girod Cemetery was deconsecrated and razed to make way for urban development. In 1974 a threatened demolition of the expansive, deteriorating wall vaults in the city's second-oldest remaining cemetery, the Catholic burial ground St. Louis Cemetery No. 2, led to the creation of the organization Save Our Cemeteries Inc., one of the oldest extant cemetery preservation organizations in the United States, which fought successfully to halt the demolition and ultimately to restore the wall vaults.

Soon thereafter, THNOC committed to funding a large-scale project, envisioned by D. Clive Hardy of the University of New Orleans, to document nine cemeteries whose continued existence was then very much in doubt. Between 1981 and 1983, in collaboration with Save Our Cemeteries and the University of New Orleans, the Survey of Historic New Orleans Cemeteries was created. The nine cemeteries included were St. Louis No. 1 and No. 2, Lafayette No. 1 and No. 2, St. Joseph No. 1 and No. 2, Odd Fellows, Greenwood (its historic portion), and Cypress Grove. The survey is comprised of black and white photos of each tomb, data from the inscriptions engraved on each tomb's pediment or closure tablet (which, in addition to names and dates, may include place of birth, military service, and the like), information regarding the material of the closure tablet and its condition, and, finally, an index. Thanks in part to the work that went into this survey project and the great interest and concern that it awakened in the community, none of the nine cemeteries surveyed was demolished.

Between 2001 and 2003 graduate students from the Weitzman School of Design at the University of Pennsylvania (Penn Design) began a project called "Dead Space" that mapped and analyzed the tombs in St. Louis No. 1, based on the data in the 1980s survey. Building on this methodology, in 2012 Penn Design completed a second such project for St. Louis No. 2. Its updated condition reports for the more than 1,180 tombs in that cemetery are included in the current database.

In that same year, 2012, THNOC undertook a project to digitize the entire 1980s survey, beginning with the tomb photos and survey index cards for St. Louis No. 1 and No. 2, the two oldest cemeteries in the city. As part of an ongoing internship and exchange program with the École nationale des chartes in Paris, in 2013 and 2014 students from its Master of Digital Technologies Applied to History program developed a beta version of the online relational database that would later evolve into the current one. Over the next few years, data from the survey's index cards were entered by students from Tulane University's Center for Public Service and by staff and volunteers at Save Our Cemeteries.

In 2017 a further collaboration was established among THNOC, Tulane School of Architecture's Master of Preservation Studies program, and Save Our Cemeteries. With funding from the Christovich Excellence Fund for Historic Preservation, made possible through the generosity of Mary Louise Mossy Christovich, and in partnership with Tulane University Law School, work began on fleshing out the beta version of the website and building the current one. Researchers may now explore the data and photos via a variety of searchable data elements, including names, dates, places of origin, and the physical/architectural characteristics of tombs. The database also takes advantage of advances in GIS mapping technology, allowing users to access individual tomb data via geocoded aerial photos of the cemeteries. The mapping of St. Louis No. 1 and No. 2, and additional contributions, were provided by the Gambrel & Peak historic preservation consulting company. Supplemental (noninteractive) maps of the two cemeteries were provided by New Orleans Catholic Cemeteries and the Archdiocese of New Orleans.

The cemeteries have endured a significant loss of material and information in the decades that have passed since the 1980s survey was completed. Although a certain number of tombs may not have borne inscriptions even when first built, countless closure tablets that once marked tombs have been stolen, destroyed, or lost to environmental deterioration, making that survey the only easily accessible source for information on who is interred behind these now-unmarked vault and tomb walls—thus, the survey's most important feature may be that it links names with tombs that might otherwise be anonymous.

In coming years, data from the remaining seven cemeteries that were included in the original survey—and, ideally, from other historic New Orleans cemeteries that were not—will be added to this database. Additional manuscript, print, and online resources will be cited as they become available, and to this end we welcome input from our users. We hope that, more than ever, the survey will be used as it was intended: as a crucial tool in the ongoing efforts to save our precious cemeteries from loss and destruction.