Legal Files is comprised principally of the records of Henry Landon in his various official capacities, such as justice of the peace in Suffolk County (circa 1820s-1850s); estates executor; officer of an incorporated religious society in Cutchogue; and officer in Southold's Democratic-Republican party. The series also includes documents related to Jared Landon's tenure as justice of the peace in the late 1700s and early 1800s. Some documents pertain to the Landons' personal legal matters, including a case concerning Henry and Samuel H. Landon (and, after his death, Samuel's estate) related to land takings for the Long Island Railroad. Much of the material appears to consist of drafts, copies, or transcriptions.

Document forms in the series that relate to court matters include court filings, court orders, decisions, testimony, subpoenas, complaints, trespasses on cases, proxies, witness statements, deeds, indentures, and wills and other estate execution papers. Court cases primarily concern matters of indebtedness, but also include theft, assault, rape, fraud, bastardy, and murder.

Southold town matters represented in the series include local elections, indentures for the overseers of the poor, town meetings, public notices, extracts from town records, judgments, and petitions against liquor licensing. Southold Democratic-Republican party matters include notices of meetings, delegate elections, and resolutions concerning national political events.

There are several corporate matters represented in the series, including dividend announcements and other documents from various whaling and fishing ventures, and draft articles of incorporation for the artillery company under the command of Capt. Silas Horton, the Education Society of Southold, the Moral Society of Southold, and the Suffolk County Anti-Slavery Society.

The series includes legal matters related to the American Revolution. These include complaints from Flushing farmers recorded against one Col. Archibald Hamilton during the war, records of takings of oxen and other property, and post-war pension claims.

The series includes various documents with reference to African-Americans. Those identified during processing include court cases in which African-Americans were charged with attempted rape, burglary, and larceny, as well as cases in which African-Americans appear as witnesses and seek relief from a (presumably white) man who imposed himself on a family. In addition, African-Americans appear as debtors to Dr. Tuthill's estate, members of Cutchogue's religious society, and a wagon driver (in connection with the complaints against Col. Hamilton).

Although the bulk of the series concerns Suffolk County and Southold in particular, there is a set of miscellaneous legal documents from the 1700s concerning other jurisdictions in New York, Connecticut, New Jersey, Rhode Island, and Virginia. Among the more notable New York documents are a 1793 Flatbush land indenture, a circa 1730 deed of trust in favor of a Presbyterian Church in Manhattan, and a 1794 assault complaint by a Brooklyn (Gowanus) resident.

The bulk of Correspondence is directed to Henry Landon concerning various legal, business, political, and New York State legislative matters. Among the letters to Henry concerning national political affairs are those from U.S. Congressmen Abel Huntington (1834) and Charles A. Floyd (1842). Among the letters concerning local political and legislative matters is an 1847 letter from the Sag Harbor trustees to Henry, in his capacity as State Assemblyman, proposing legislative amendments to Sag Harbor's act of incorporation. Correspondence concerning Landon's dealings with the Long Island Rail Road in connection with land acquisition is in the series.

The series also includes correspondence between Jared Landon and his father, Samuel, from the period in which Samuel was a refugee in Connecticut during the British occupation of New York City. The series includes Jared's 1778 petition for release from military prison. Several pieces refer to wartime hardships on Long Island. Other correspondence to Jared includes an 1814 letter from U.S. Congressman Ebenezer Sage in which Sage expresses his fear that Britain intends to recolonize America.

Other correspondents include, among others, Phineas Corey, David Conkling, Stephen Conkling, Joshua Fleet, and Daniel Osborn. The series includes correspondence of 1862-63 to Colonel W.B. Barton, commander of the 48th Regiment of New York State Volunteers in South Carolina, from Confederate commanders regarding movements under flags of truce. An 1836 document to Henry describes the facts of a case to be decided in which an African-American girl of about 10, originally bound by her mother to a Mr. Smith, sought to remain bound to Smith, rather than be taken away by her brothers upon the death of her mother. The series also includes an undated circular letter from "The Ladies" giving playful encouragement to the public speaking endeavors of the "Younger Members" of the Cutchogue Young Men's Debating Society. In addition to the commercial, legal, and political matters that predominate in the series, some of the correspondence is also concerned, at least in part, with matters of health and religious fervor.

Financial Records generally consists of material from the late 1700s that concerns estate cases handled by Jared Landon and from circa 1820-1860 that concerns various financial matters of Henry Landon. Formats include day books, ledgers, vendue (auction) accounts, inventories, promissory notes, account statements, receipts, invoices, sales agreements, and the like.

For the late 1700s, the series consists of an extensive set of business and estate settlement records for merchant David Conkling of Southold, deceased 1787. Records of two other Conklings, Stephen and Joseph, are also found with David's estate records, for which Jared Landon and Stephen were co-executors. There are several account books (i.e., day books, ledgers, journals) in the series; although most cannot be directly traced to an owner, it is possible that some of these relate to David Conkling. Conkling-related documents include those concerning the Conkling-owned sloop Seaflower.

Other financial records from the late 1700s and early 1800s likely concern Jared Landon personally or were related to other professional matters he worked on, but these are less clear and less extensive than material directly associated with the Conklings. Among these documents is a 1790 receipt for a subscription to the Gazette of the United States, signed by John Fenno.

The material holds several documents related to African-Americans. Various day books, journals, and transaction documents contain references to African-Americans executing transactions on behalf of others or for themselves, including transactions with the Conkling estate. The series includes a 1793 levy from a collector indicating that a "negro boy" would be taken in partial payment of an assessment for street improvements.

From circa 1820 to 1860, the series includes extensive financial records of Henry Landon. These records primarily concern his personal affairs, most notably a detailed account book for the period 1815 to 1853. The miscellaneous financial documents consist of standalone items whose salient features consist of calculations, accounts, and other numbers-oriented notes. Records of expenses incurred on travel, weights of hogs, value of fish taken, bushels of produce, and other such data can be found in Henry's records.

Miscellaneous includes a broad mix of documents that defy broad categorization. The series includes documents related to Jared and Henry Landon which either did not clearly fit into the other series or had mixed content. The series includes Jared Landon's 1857 school workbook with arithmetic exercises and poetry, and which was also used in later decades for records of various accounts, a list of wills transmitted to New York, and an agreement among the heirs of Samuel Landon. Other material related to Jared includes a Revolution period character reference from a British officer and several printed New York State acts of legislation. Papers associated with Henry include a record of the heads of skunks and blackbirds presented to Henry for bounties. The bulk of Henry's papers in this series include documents that include a mix of matters (e.g., both financial and legal matters).

Other material in the series from the American Revolution period includes an account by one Col. Popham of his part in the Battle of Long Island; an unsigned 1777 "Memoire," or reflection, on the development of the Revolution and its international implications; a transcription of a 1779 Congressional resolution; and Daniel Youngs's journal of his detention in the Provost prison during the Revolution (1778) and his writings from Connecticut. The series also includes a journal of the 1792 proceedings concerning a treaty with Indian nations from Wabash and Illinois country at Post Vincences, conducted by Brigadier General Rufus Putnam. Other items in the series are identified in the container list. The series closes with a few uncategorized items and fragments.