The papers of Lammot du Pont (1831-1884) describe his innovative work in the explosives industry, his outside investments in coal mines and railroads, and his correspondence with family members. Among the papers are his travel correspondence during his time as DuPont Company representative in Europe in 1858 and from 1861 to 1862 as a confidential agent of the United States government to purchase saltpeter for gunpowder production needs during the United States Civil War. There is also a small subset of materials compiled by his son, also named Lammot du Pont (1880-1952), on various du Pont family and company historical topics.

The papers are arranged into the following six series: I. General correspondence; II. Technical papers and European company correspondence; III. Mining and railroad papers; IV. du Pont family correspondence; V. Military and bank papers, drawings, certificates, textile mill notes, student work, and other miscellany; and VI. Lammot du Pont (1880-1952) papers on family and company history

Series I (formerly Series A)

The general correspondence includes both personal and business papers. In addition to letters of family and friends and items reflecting Lammot du Pont's interest in science education, there are letters relating to powder-making machinery and material on the Gunpowder Trade Association (with particular reference to territorial disputes, price cutting, and mergers), railroad interests, and coal orders. While primarily loose correspondence, the series also contains two letter books, the content of which deals largely with the powder trade and related business matters.

Series II (formerly Series B)

The papers in this series relating to the manufacture of explosives describe all phases of powder making and augment the official records of the E.I. du Pont de Nemours & Co. records (Accession 0500.I). They include accident and explosion records, dating from circa 1805 to 1879, patents, testing, papers relating to production costs, and advertising material, including a collection of foreign and domestic gunpowder labels. This series also includes material on the Gunpowder Trade Association, including Henry M. Boies' original proposal for organization, agreements with member companies, syndicate price lists, minutes of meetings, and papers concerning the purchase of Brainerd Mills, circa 1868-1880; patents (among which are certain ones of Alfred Nobel), 1829-1880; miscellaneous business papers relating to production costs, accounts, and agreements with companies, dating from 1838 to 1883.

Additionally, there are numerous notes and papers concerning ingredients and processes involved in powder making. Most numerous are items relating to: experiments with saltpeter, charcoal, and sulfur, conducted by Alfred Victor du Pont (1798-1856), Alexis I. du Pont (1816-1857), and Lammot du Pont; the processes of glazing, refining, and rolling; the operation of machinery; performance and firing qualities of powder. In testing, much of the experimental work was done by the United States government, as indicated by correspondence between Alfred Mordecai and Alfred V. du Pont, particularly on guncotton, 1841-1849, and later letters between the company and the Ordnance Office relating to tests of Mammoth powder, 1869-1871.

A smaller group of material dating from 1857 to 1862 relates to Lammot du Pont's trips to Europe as a company representative. In 1858 he went as an observer, but from 1861 to 1862, he was there as a confidential agent of the government to purchase, in the name of E.I. du Pont de Nemours & Co., an adequate supply of saltpeter for wartime production needs. Among the significant items are: correspondence between Lammot du Pont and Henry du Pont (1812-1889), then head of the company, discussing his intentions, movements, and accomplishments while abroad; a letter of introduction from President James Buchanan (1791-1868), 1858; a request for a personal loan from John Y. Mason, American Minister to France (1799-1859), 1858; a letter of J.R. McDonald, vice-consul at Hamburg, to Benjamin Moran (1820-1886), assistant secretary of the American legation at London, discussing the supply of saltpeter, 1862; and letters of James Antoine Bidermann (1790-1865), A.D. Bishop (of London), H.E. Drayson (London agent), Alfred V. du Pont (1833-1893), Margaretta (Lammot) du Pont (1807-1898), Forbes, Forbes & Co. (London agents), Henry Hall Gage (1791-1877) (Viscount Gage of Castle Island (Kerry)), Peter Kemble (1825-1887), Lloyd's of London, and others.

Series III (formerly Series C)

The mining and railroad papers relate to Lammot du Pont's outside investments. The chief mining enterprise was the Mocanaqua Coal Company, of which du Pont was president in the late 1860s. It was a small mining company near the Wapwallopen Mills in Luzerne County, Pennsylvania. There was a period of instability in the anthracite coal industry, marked by competition and consolidation of firms and attempts to organize the mine workers. The records describe how these trends soon prompted du Pont to sell the company. The Mocanaqua material is chiefly correspondence, much of which is addressed to C.L. Foxwell and C.H. Gallagher, agent, and salesman, respectively, and concerns orders for coal.

Other mining papers describe du Pont's search for soda deposits of soda, sulfur, and saltpeter to manufacture gunpowder. These papers contain analyses of samples, reports on claims, and correspondence, including mentions of interactions with Indigenous Americans. These papers include letters written by frontiersman Boney Earnest (1845-1933).

The railroad papers concern the construction and management of the Wilmington & Reading Railroad, which linked the du Pont mills with the Reading Railroad system, and its reorganization as the Wilmington & Northern in 1877. There is also data on the reorganization of the Berks County Railroad and its subsequent leasing to the Philadelphia & Reading Railroad. The bulk of this material is correspondence about finances and stock matters, but there are also lists of bondholders, proxy statements, reports to stockholders, agreements, and memoranda.

Series IV (formerly Series D)

The family correspondence chiefly concerns daily events of family life but with numerous references to E.I. du Pont de Nemours & Co. and the Repauno Chemical Company, including drafts of powder agreements, reports on the operation of the Wapwallopen Mills, shipments of supplies, powder mill explosions, and plans for repairing the mills. The letters are primarily to Lammot du Pont, but include some between other family members. The letters describe family matters, such as illnesses, school life, and friendships.

Series V (formerly Series E)

The Military and bank papers, drawings, certificates, textile mill notes, student work, and other miscellany includes records of Lammot du Pont's Civil War service, correspondence concerning the Louviers woolen factory and the Rockland cotton mills, and several hundred drawings of houses, mills, and machinery, and bridges. The papers relating to du Pont's military service include reports, muster rolls, receipts, and correspondence. Bank papers include canceled checks and promissory notes from the Union National Bank, Philadelphia National Bank, and First National Bank of Reading. This series also includes school copybooks and sketchbooks of various members of the du Pont family. There is also a scrapbook containing an assortment of postmarks from across the United States. Finally, there are a few items related to transportation, various printed items, stock certificates, memberships, and diplomas.

Series VI (formerly Series F)

This series, presumably compiled by Lammot du Pont (1880-1952), consists primarily of copies of early letters and notes pertaining to DuPont Co. and du Pont family history, with memoranda of Lammot du Pont and others of the family concerning the items. Of particular interest is the correspondence of Thomas S. Grasselli (1874-1942) and others regarding the role of Lammot du Pont (1831-1884) in supplying powder for the Crimean War.