ABSTRACT The city of Youngstown, the county seat of Mahoning County, is situated along the Mahoning River in northeastern Ohio, USA. Its early industrial growth was due to the ready availability of iron ore, limestone, abundant forests, and coal, all used for production of iron and then steel during the last two centuries. Local Massillon sandstone and Vanport limestone from Ohio and western Pennsylvania were used to construct mansions and other structures in the nineteenth century. By the early 1900s, other stones including Berea sandstone from Ohio, and sedimentary, metamorphic, and intrusive igneous stones quarried at other sites in North America and Europe, were being utilized as dimension stone in Youngstown. This guide briefly reviews the geological and cultural setting of Youngstown, and describes the building, decorative, and monumental stones used for a variety of structures in downtown Youngstown, with emphasis on stone used for the exterior and interior of major structures. Sites include the Butler Institute of American Art, which is clad with marble and incorporates an assortment of other stone inside and outside of the complex, and St. Columba Cathedral, whose limestone is known commercially as Mankato ( Kasota ) stone and is full of fossil burrows, as well as a sampling of stones used in beautiful Oak Hill Cemetery.