This small collection of Lea family papers documents Delaware and Pennsylvania land use and ownership, elite family and social relationships, and agricultural business operations of the early eighteenth century to the mid-nineteenth century. The materials are from four generations of the William Lea (1805-1876) family lineage. The collection is arranged into four series: Real estate and financial papers, Correspondence, Personal papers, and Newspaper clippings. Each series is arranged chronologically.

The Estate and financial papers series documents Delaware and Pennsylvania land use and ownership from the early seventeenth century through the mid-nineteenth century. In particular, the materials document the importance of water and water rights in the development of regional and national economies, as well as the work involved in the Lea family's pursuit of reliable supply chains, new distribution options, desirable machinery, and good engineering across a considerable geographical extent.

The series includes land indentures, deed transfers, mortgage claims, land patents, and land surveys of the Lea, Tatnall, and associated families that mostly date from the latter part of the eighteenth century. There is an English royal patent of 1679 recording the grant of lands along Delaware's Cristiana Creek, present along with a 1770 report adjusting ownership of the land parcels surveyed in 1675. An indenture of 1779 records a transaction between Benjamin Chew and Samuel Meredith relating to Chew's sale of 5,400 acres in Northumberland County, held by him in warrant from the Pennsylvania Proprietary Land Office from 1774. The indenture refers to another quinquepartite indenture of 1775 accomplished among Chew, Meredith, Edward and Joseph Shippen (Jr.s), and Andrew Allen, all of Philadelphia, relating to the land and its several defining waterways, with wood and water rights being specifically addressed. Notably, there is a 1792 survey map by Thomas Piersons and an 1815 property map of the Tunkhannock Creek area. The Tunkhannock Creek map shows, with the aid of a detailed color-coded key and color-coded outlining, the tracts belonging to Edward Shippen Jr., Joseph Shippen Jr., and Andrew Allen. The map plots the disposition of the Philadelphians' water-adjacent lands (and more) to named individuals, some of whom have multiple lots. Sarah Lea and her son, William Lea, are the principal parties in a deed of 1838 that concerns a holding of nearly 2,000 acres in Northampton County, Pennsylvania. Included are also the estate papers for William Lea III and his sister, Jennie Lovett Lea Ford.

The Correspondence series contains a disparate set of letters, in which very few share the same composer or recipient. However, the personal letters are between family members, and there is business correspondence related to the Lea family flour mills. Even the family letters include business travel, business news, and business ideas appearing alongside personal news.

Business correspondence is also present from non-family members, such as friends John and Robert Morton, who warn the Tatnall & Lea partners in 1786 of a possible bad transaction in process, and representatives of C. Pusey & Co., who in 1827 document a $5,000 order (this bearing hand-drawn seals). Additionally, there are two letters of introduction for English mechanic/inventor William Pearce, one sent by Thomas Digges in 1791 from Belfast to an unnamed recipient and the other sent by an identified sender to Tatnall & Lea. William Pearce is credited with inventing the double loom for weaving cotton. Both letters of introduction ask that Pearce be welcomed and introduced to others due to his knowledge of milling machinery.

Letters shared between family members mix personal and business news, such as Joseph Lea's 1805 letter to his father, Thomas Lea, detailing intelligence on Robert Morris' financial failure. Edward Tatnall's 1828 letter to Thomas Lea is almost entirely devoted to commentary on the energetic virtues of Americans and the business advantages associated with them as compared to the lack of industry and ambition found on a recent visit to Ontario. Henry Lea, writing his brother, William Lea, is partway through what appears to be his first independent business trip focused on finding new sources for good wheat; he starts by asking how a planned hunting ("gunning") party has gone. John Lea writes to his sister-in-law from New Haven in 1813, reporting that "to my great disappointment I have not seen Whitney's Ginn [sic] Factory," and that he cannot talk to his father or brother about girls.

The Personal papers series consists of an array of materials related to social, educational, and leisure life. There are two illustrated student math notebooks, one belonging to William Lea and the other belonging to his brother, Henry Lea. Of their elder brother, Edward Lea, there is an empty "Geographical Cards" game box and two University of Pennsylvania enrollment course receipts. Materials also include magazine subscription receipts for the Saturday Evening Post and the Living Age, a Lea family bookplate featuring the family's coat of arms, a lacy handkerchief, an emboidered pocket purse, a red satin prize ribbon, Jane S. Lea's committee ticket to the 1864 Great Central Fair in Philadelphia, and a typescript of Jennie Lovett Lea's speech to the members of the Women's Auxillary about membership. There are three photographs: one daguerreotype of Caleb Bentley; a portrait of William Lea Jr.; and a snapshot of a woman in front of a Toledo, Ohio, home during the 1920s, presumably Ora Adele Wickler Lea. The series also contains the last will and testament of Edward Robinson and the marriage certificate and wedding invitation of William Lea, Jr. and Sarah Brooke Bentley.

The Newspaper clippings series consists of articles related to family members' personal lives, deaths, and business affairs. There are obituaries for Sarah Tatnall Lea; her son, William Lea; his wife, Jane Scott Lovett Lea; and one of their daughters, Mary Lea. The business memorabilia consists of a newspaper advertisement saved from the Daily Commercial for Wm Lea & Son's flour (1869) and a cardboard trade card issued by the firm for its "Choice Family Flour" ("Mills: Brandywine & New Castle"). The trade card offers a view of one of the mills on its verso. There is an article about a fire at the mill and the flour trade in general. Of particular interest is a set of embroidery patterns clipped from Toledo, Ohio, newspapers, as well as hand-drawn patterns dated from 1908 through 1920, most likely collected by Ora Adele Wickler Lea. Many have prick holes, demonstrating their use. Transfer paper, embroidery instructional articles, and sketches are also included.