Tombstone is a historic western city in Cochise County, Arizona, United States, founded in 1879 by Ed Schieffelin in what was then Pima County, Arizona Territory.It was one of the last wide-open frontier boomtowns in the American Old West.The town prospered from about 1877 to 1890, during which time the town's mines produced US$40 to $85 million in silver bullion, the largest productive silver district in Arizona.n the evening of March 15, 1881, three Cowboys attempted to rob a Kinnear & Company stagecoach carrying US$26,000 in silver bullion (about $635,386 in today's dollars) en route from Tombstone to Benson, Arizona, the nearest railroad freight terminal.