Abstract By virtue of its use in iconic monuments and historic buildings in the USA, Cockeysville marble, a dolomitic to calcitic lower Paleozoic (Cambrian/Ordovician) marble quarried in Baltimore County and adjacent areas in Maryland, is proposed as a potential Global Heritage Stone Resource. The most important use of this stone was for the Washington Monument in Washington, DC whose construction began in 1848; the second most important use was for the 108 columns of the United States Capitol's wings, completed in 1868. It was also used for two of the oldest major marble monuments in the USA, Baltimore's Battle Monument (dedicated in 1827) and Washington Monument (completed in 1829), as well as Baltimore's City Hall, Buffalo's Adkins Art Museum, Detroit's Fisher Building and parts of St Patrick's Cathedral in New York City. During the nineteenth century white Cockeysville was most desired, but a colourful variety, Mar Villa marble, was also used in the first decades of the twentieth century. Cockeysville marble is no longer quarried for dimension stone. All Cockeysville used outdoors has weathered to a lesser or great extent, but early testing indicating that the dolomitic marble would be more durable has proved to be true.