Borough Municipal Offices are located at 424 Main Street, Irwin PA 15642.
Irwin borough is located twenty-two miles east of Pittsburgh, on the Pennsylvania railroad, and is situated in the center of the bituminous coal region of that section. When the railroad was first built, land upon which it now stands was covered with timber, mainly large white oak. In 1844 there was only one house there, which was owned by Thomas Shaw. John Irwin, founder of the town, laid out the first plan of lots in September, 1853. The building-up of the town of Irwin has been brought about by the coal industry. Shortly after the Pennsylvania railroad was built, Thomas A. Scott and William Larimer began to open up coal mines and ship coal on the railroad to distant markets. This business they carried on until 1856. when they sold out to the Westmoreland Coal Company, which had been incorporated in July, 1854. It is now and has been for almost a half a century one of the largest coal mining companies in Pennsylvania. Its chief incorporators were General William Larimer, who was the largest stockholder, Thomas A. Scott and John Covode, all of whom have since become eminent in our history.