Jacob was born on May 30, 1800 at Somerset County, Pennsylvania, United States. He was of English-Welsh descent, the sixth and youngest child of Isaiah and Rachel (Reed) Strawn, who were Quakers. His great-grandfather, Lancelot Straughan, had settled in Pennsylvania in the first decade of the eighteenth century.
Attending the district school for a few months each winter, he received a meager education.
In 1817 Strawn moved with his parents to central Ohio. After working for his father until 1819, he settled on a nearby farm and began farming and dealing in live stock for himself. In 1828 he bought 395 acres of land about four miles southwest of Jacksonville, Illimois.
Moving to this farm in May 1831, he began the operations which earned for him the title of "cattle king, " extending his holdings in Morgan, Sangamon, and LaSalle counties until he held over twenty thousand acres, chiefly in two tracts. Except for the first few years, when he raised wheat and engaged in milling and butchering, he devoted his Illinois land to timber, pasture, and corn.
In 1854 he raised 2, 900 acres of corn, all of which was fed to stock, and owned 2, 000 cattle, 700 hogs, and more than a hundred horses and mules. Later he was reputed to have fattened more than five thousand cattle in one year. He introduced into Illinois the practice of feeding shock corn to cattle. He bred few cattle, preferring to buy, fatten, and sell. On horseback he scoured central and southern Illinois, Missouri, and the settled parts of Iowa for feeder cattle which he drove to his Illinois farms. Here they were fattened for the markets in the East, New Orleans, and St. Louis. On one occasion, to thwart a conspiracy of buyers to break his hold on that market, he sent agents out on all the roads leading into the city and bought all incoming herds. He broke the combination in two days and had no more difficulty of that kind.
After 1850 he began to confine himself largely to grazing and feeding and to market more of his cattle at home. In the last few years of his life he curtailed his operations. He died in 1865.
Although he made no profession of religion, he was sympathetic toward it.
He was a Whig and a Republican, but sought no office. During the Civil War he actively supported the Union and aided in relief work among Union troops.
He believed in hard work and in frugal, simple living, despised show, was plain in dress and rough in speech. He was scrupulously honest, prompt in his dealings, sympathetic toward those in distress, had a strong sense of honor, and commanded universal respect.
Possessed of a powerful physique and a strong constitution, he was an active man, spending most of his time outdoors, much of it in the saddle. He abstained from the use of tobacco and liquor, and declined to serve the latter to his harvest workers.
In 1819 he married Matilda Green, daughter of John Green, a Baptist minister of Licking County, Ohio. She died in 1831 after having borne seven children.
The following year he married Phoebe Gates, daughter of Samuel Gates of Greene County, Illinois. By this marriage he had five sons and a daughter.
