Between 1842 and 1859, at least 20,000 people died on the overland trail, an average of ten graves per mile along the 2,000-mile route. Of the hundreds who died while crossing Nebraska, only seven identifiable graves remain. Most trail graves were marked with crude wooden or animal-bone markers, while a few had formal stones or iron wagon wheel rims. The nearby grave of John Hollman, like others in western Nebraska, was marked by a roughly fashioned local rock, and unlike most of the others it still stands, bearing crude lettering with his name and the fact that he died in June 1852. Many overland travelers died from accidents, a few were killed by Indians, and the great majority died from disease. Asiatic cholera was the main killer, coming up the Mississippi from New Orleans, and parties crossing Missouri spread it across the Plains. How John Hollman died is not known, but 1852 was a very bad cholera year and numerous deaths were recorded in this vicinity. Wagon ruts are still visible in parts of Garden County, and local rock formations noted by many diarists remain as part of this historical heritage.