Lewis Cass, an American statesman, born at Exeter, N. H, Oct. 9, 1782, died in Detroit, Mich., June 17, 1866. He was the eldest son of Jonathan Cass, who served in the revolution and rose to the rank of major in the army. In 1799 he was stationed at Wilmington, Del., where his son found employment as a teacher. In the following year the family went to Marietta, Ohio, where Lewis studied law, and in 1802 he was admitted to the bar and began to practise in Zanesville. In 1806 he married Elizabeth Spencer, of Wood co., Va., and shortly afterward was elected a member of the legislature. In this capacity he drew up the address to Jefferson embodying the views of the legislature on Aaron Burr's expedition, and drafted the law under which Burr's boats and provisions, built and collected in Ohio, were seized. From 1807 to 1813 he was state marshal. In the war of 1812 he was colonel of the third Ohio volunteers under Gen. Hull, and after Hull's surrender was appointed colonel of the 27th infantry, and was shortly afterward promoted to the rank of brigadier general. At the close of the campaign he was in command of Michigan, and in October, 1813, was appointed governor of the territory.

He acted as governor, and ex officio as superintendent of Indian affairs, for 18 years, during which time he negotiated 22 treaties, secured by cession of different tribes immense tracts of land in the northwest, instituted surveys, constructed roads, built forts, and organized counties and townships. In 1815 he purchased for $12,000 a homestead tract of 500 acres in Detroit, which the subsequent growth of the city made immensely valuable. In 1820, in company with Schoolcraft and others, he explored the upper lakes and the head waters of the Mississippi, traversing 5,000 miles. The results of this and of subsequent expeditions were published in the "North American Review" in 1828-'9. In 1831 President Jackson nominated him secretary of war, and he was at the head of the war department during the first two years of the Florida war, 1835-'6. In 1836 he was sent as minister to France. In this capacity he settled the indemnity dispute by obtaining the interest withheld when the principal was paid. In 1837 he embarked at Marseilles in the frigate Constitution for Egypt via Constantinople, following the coast, stopping at the principal ports, and making excursions into the interior.

He was on excellent terms with Louis Philippe, of whose character he gave a favorable account in his "King, Court, and Government of France," published in 1840. The most marked incident of his diplomatic career was his attack on the quintuple treaty for the suppression of the slave trade, which led to his resignation in 1842. In January, 1845, he was elected United States senator from Michigan, which place he resigned on his nomination, May 22, 1848, as democratic candidate for the presidency. A division in the democratic party in New York gave that state to Gen. Taylor, and secured his election by a majority of 36 electoral votes. In June, 1849, Cass was reelected to the senate for the remainder of his original term. In the next session he vigorously opposed the Wilmot proviso, though he was instructed by the legislature of Michigan to vote for it. In 1850 he was a member of Clay's compromise committee, but did not vote for the fugitive slave bill. He was again elected a senator for six years from March 4, 1851. In the democratic convention at Baltimore, in May, 1852, he was a candidate for the presidential nomination, but was unsuccessful.

In 1854 he voted for Douglas's Kansas-Nebraska bill proposing a repeal of the Missouri compromise, but including a provision embodying Cass's suggestion, in the famous Nicholson letter, to leave to the inhabitants of the territories the power to regulate their own institutions, subject only to the constitution of the United States. Subsequently he declined to obey the instructions of the Michigan legislature as to his votes on the Kansas question. In the democratic convention at Cincinnati, in May, 1856, he was not a candidate, and warmly concurred in the nomination of Mr. Buchanan, who on his accession to the presidency in 1857 nominated Cass as secretary of state. In December, 1860, when Buchanan refused to reenforce Major Anderson and re-provision Fort Sumter, he promptly resigned and closed a public career of 54 years. During the war he warmly sympathized with the national cause, and lived to see its complete success. He was a man of much ability and of the purest integrity, a fine scholar, and an effective public speaker. In private life he was distinguished for a generous hospitality, which his great wealth enabled him to dispense.

Besides his published works above noticed, he was author of an " Inquiry respecting the History, Traditions, Languages, etc, of the Indians living within the United States " (Detroit, 1823), and of several historical and scientific sketches and addresses. - See "Life and Times of Lewis Cass," by W. L. G. Smith (New York, 1856).