These data include giant sequioa (Sequoiadendron giganteum) age and tree-ring data from measurements on 458 stumps. The original data were recorded on paper data sheets by Ellsworth Huntington and his assistants in 1911 and 1912; their methods are elaborated in Huntington (1914), and further details can be found in Stephenson and Demetry (1995). We entered the data from photocopies of the original data sheets which, to the best of our knowledge, reside at Yale University. The photocopies apparently were made in the late 1960s or early 1970s and were housed in Sequoia National Park’s archives. Most of Huntington’s 458 measured giant sequoia stumps were in or near what is now the Hume Lake District of Sequoia National Forest (Giant Sequoia National Monument), California, particularly the Converse Basin Grove; however, about 17 percent came from in or near what is now Mountain Home Demonstration State Forest, about 70 km to the SSE. Data for each tree (stump) consist of from one to five readings of the widths (to the nearest 0.5 mm) of groups of 10 tree rings along unique radii. When only one or two radii were measured on a stump, we entered the data for each radius. When three, four, or five radii were measured, we entered data from two radii whose directions differed by at least 90 degrees, whenever possible. The choice of entering data from widely separated radii was made by Stephenson and Demetry (1995), who wished to determine the effects of two widely separated increment cores on the accuracy and precision of age estimates for giant sequoias. Sometimes, “DO NOT USE” was written by Huntington across a radius’ readings, usually because that radius came out several to many decades younger than the oldest radius for that tree. If such a radius normally would fit our criterion to be entered in the database (because it was separated by at least 90 from the other radius we entered), a judgement was made. Generally, if the difference was at least 50 years, a different radius whose count better agreed with the largest count was chosen, regardless of its direction. References: Douglass, A. E. 1919. Climatic Cycles and Tree Growth, A Study of the Annual Rings of Trees in Relation to Climate and Solar Activity. Carnegie Institute of Washington. 127 pages. Huntington, E. 1914. The Climatic Factor as Illustrated in Arid America. Carnegie Institute of Washington Publication No. 192. 341 pages. Stephenson, N. L., and A. Demetry. 1995. Estimating ages of giant sequoias. Canadian Journal of Forest Research 25:223-233.