US Congressman, US Diplomat, 10th Mayor of Pittsburgh, Pennsylvania. He was born one of eight children (John Scull Irwin was born in 1798, Mary Taylor was born in 1804, Agnes Mary Irwin was born in 1805, Frances Mason Irwin was born in 1809, David Irwin was born in 1811, Eliza Irwin was born in 1812, and Margaret Polly Irwin was born after 1812), of Scottish and Irish ancestry to John Irwin and Agnes Nancy Farquhar Irwin in Pittsburgh, Pennsylvania. He was educated locally and attended private school in Pittsburgh, Pennsylvania, and then attended the Allegheny College in Meadville, Pennsylvania. He then studied law and was admitted to the Allegheny County, Pennsylvania, bar on May 6, 1828, and commenced to practicing law in his hometown of Pittsburgh, Pennsylvania. On September 24, 1829, he married Frances Everallyn Rose (she was the niece of Illinois Supreme Court Justice Theophilus W. Smith and aunt of the bridge engineer Charles Shaler Smith), in Pittsburgh, Pennsylvania, and the couple would have four children together (Frances Mason Irwin was born in 1830, John Irwin (later a Rear Admiral in the United States Navy) was born in 1832, Charlotte Wyman Irwin was born in 1834, and William Irwin was born in 1836). In 1835, he served as the President of the Western University's Alumni Association. His first wife Frances passed away on February 24, 1836, at the age of 26, in Pittsburgh, Pennsylvania. He then decided to run for the office of the Allegheny County, Pennsylvania, District Attorney and was successfully elected to that post and served in 1838. He married for the second time to Sophia Arabella Bache (she was the daughter of Richard Bache, Jr., who served in the Republic of Texas Navy and was elected as a Representative to the Second Texas Legislature in 1847 and Sophia Burrell Dallas, the daughter of Arabella Maria Smith and Alexander J. Dallas an American statesman who served as the United States Treasury Secretary under President James Madison. She was also the granddaughter of Sarah Franklin Bache and Richard Bache, the great-granddaughter of Benjamin Franklin, and a niece of George Mifflin Dallas, the 11th Vice President of the United States, serving under James Knox Polk) on February 28, 1839, in Washington, D.C., and the couple would have eight children together (John Monroe Irvin was born in 1832, Frances E. Irwin was born in 1833, Richard Biddle Irwin was born in 1839, Agnes Irwin (later a famous educator) was born 1841, Robert Walker Irwin (later a famous businessman and the Kingdom of Hawaii's Minister to Japan) and was born in 1844, Sophia Dallas Irwin was born in 1845, Robert M. Irwin was born in 1846, and Mary Bach Irwin was born in 1849). He then ran for the office of Mayor of Pittsburgh, Pennsylvania, and was elected. He served as the 10th Mayor of Pittsburgh, Pennsylvania, from 1840 to 1841. As Mayor of Pittsburgh, Pennsylvania, he helped with the expansion of the city's infrastructure and four additional wards were created under his administration. After his term as Mayor of Pittsburgh, Pennsylvania, expired in 1841 he was succeeded in office by incoming Mayor James Thomson. He then decided to run for a seat in the United States Congress and was elected. A Member of the Whig Party, he then served Pennsylvania's 22nd District (Twenty-Seventh Congress) in the United States House of Representatives from 1841 to 1843. He was not a Candidate for reelection in 1842. After his term in the United States Congress expired on March 3, 1843, he was succeeded in office by United States Representative Samuel Hays. He lastly was appointed by then-President John Tyler to the position of United States Chargé d'Affaires to Denmark and served from March 3, 1843, to June 12, 1847. He then lived the rest of his life in Pittsburgh, Pennsylvania, until his death on September 15, 1856, at the age of 53. He was buried in the Allegheny Cemetery near his first wife Frances in that city. His second wife Sophia passed away on March 24, 1904, at the age of 88, but she was buried in the Saint James the Less Episcopal Churchyard in Philadelphia, Pennsylvania.