Gladstone is a city located in Clackamas County, Oregon, United States. The population was 11,491 at the 2010 census. Gladstone is an approximately 4mi2 suburban community, 12mi south of Portland, the largest city in Oregon, and located at the confluence of the Clackamas and Willamette rivers.Gladstone has held several important cultural and social events, hosting both the inaugural Clackamas County Fair and the Oregon State Fair, before both were moved to more spacious locations. Both Secretary of State William Jennings Bryan and presidential candidate Theodore Roosevelt have given public speeches in the city.HistoryClackamas IndiansPrior to European settlement, there were several Native American groups living in the area that was to become Gladstone.In 1804, President Thomas Jefferson commissioned the Lewis and Clark expedition to explore the Louisiana Territory and beyond. Although the expedition passed only near the Gladstone – Oregon City locality on their way to and from the Pacific Ocean, via the Columbia River, natives such as the Kalapuya and the Clackamas people told them about the area.