Representative Jonas Platt

Jonas Platt (June 30, 1769 – February 22, 1834) was an American lawyer, jurist, and Federalist politician from New York who served one term in the United States House of Representatives. He was born on June 30, 1769, in Poughkeepsie, in the Province of New York, then part of British America. He was the son of Zephaniah Platt, a patriot politician and lawyer who founded Plattsburgh, New York, and his second wife, Mary Van Wyck Platt. Among his siblings was Charles Z. Platt, who later served as New York State Treasurer. Raised in a politically active and influential family, Platt grew up in an environment that connected him early to public affairs in the emerging nation.

Platt received part of his education at a French Academy in Montreal, Quebec, reflecting both the cross-border connections of the period and his family’s resources. He subsequently studied law in New York City under Richard Varick, a prominent attorney and public official who served as mayor of New York City and had been associated with Alexander Hamilton. Platt was admitted to the bar in 1790, marking the beginning of a legal career that he would combine with extensive public service at the county, state, and federal levels.

After his admission to the bar, Platt practiced law in Poughkeepsie and quickly entered local public office. He served as county clerk of Herkimer County, New York, from 1791 to 1798, a period during which the state was expanding westward and county officials played important roles in land transactions and local administration. When Oneida County was formed, Platt became its county clerk as well, serving there from 1798 to 1802. He also entered the state legislature early in his career, serving as a member of the New York State Assembly in 1796, where he began to establish himself as a Federalist voice in state politics.

As a member of the Federalist Party representing New York, Platt was elected to the 6th United States Congress and served one term in the U.S. House of Representatives from March 4, 1799, to March 3, 1801. His service in Congress occurred during a significant period in American history, as the young republic confronted partisan division between Federalists and Democratic-Republicans and navigated foreign policy challenges in the aftermath of the quasi-war with France. During his term, Platt contributed to the legislative process and represented the interests of his New York constituents. He served as Chair of the United States House Committee on Revisal and Unfinished Business, a position that placed him at the center of managing pending legislation and overseeing the completion and organization of the House’s work.

Following his congressional service, Platt resumed the practice of law in New York while continuing his involvement in public affairs and military service. He served as a general in the cavalry of the New York State Militia, reflecting the common practice of prominent lawyers and politicians holding militia commissions in the early republic. Platt returned to the state legislature as a member of the New York State Senate from 1809 to 1813. During his tenure in the Senate, he became an active and early promoter of the Erie Canal, working to advance legislation that would spur its construction and thereby support the economic development and integration of upstate New York with Atlantic markets. In 1810, he was an unsuccessful Federalist candidate for governor of New York, an indication of his prominence within the party. In 1813, he served as a member of the Council of Appointment, a powerful state body that controlled a wide range of public offices under the then-existing New York Constitution.

Platt’s public career reached its judicial culmination when he was appointed an associate justice of the New York Supreme Court, serving from 1814 to 1821. In this capacity, he participated in shaping New York’s jurisprudence during a formative period in the state’s legal history, as questions of property, commerce, and the evolving relationship between state and federal authority came before the courts. In 1821, he was a delegate to the New York Constitutional Convention, where he took part in debates over the restructuring of state government, the judiciary, and the system of appointments and suffrage. His participation in the convention reflected his long experience in both legislative and judicial branches of government.

In his personal life, Platt married Helena Livingston (1767–1859), a member of the prominent Livingston family. She was the daughter of Dr. Henry Livingston and Susannah Storm (née Conklin) Livingston and was connected to a wide network of influential relatives, including Continental Congressman Gilbert Livingston, the Reverend Dr. John Henry Livingston, president of Queen’s College (now Rutgers University), and author Henry Livingston Jr., the grandfather of U.S. Senator Sidney Breese and Admiral Samuel Livingston Breese. Jonas and Helena Platt were the parents of eight children. Among them were Susan Jonasse Platt (1793–1843), who married Richard Ray Lansing; Zephaniah Platt (1796–1871), who became Attorney General of Michigan; and Helen Livingston Platt (1798–1876), who married Truman Parmelee and, after his death, Dr. Henry W. Bell. Through these family connections, Platt’s lineage extended into political, legal, and military circles well beyond New York.

Jonas Platt died on February 22, 1834, in Peru, Clinton County, New York. He was buried in Riverside Cemetery in Plattsburgh, the town founded by his father, symbolically linking his final resting place to the family’s role in the development of northern New York. His career, spanning local administration, state legislation, national office, militia service, and judicial authority, reflected the multifaceted public responsibilities undertaken by leading Federalist figures in the early decades of the United States.