The highest point on land is the peak of Mount Everest at 29,028 feet (8,848 meters) above sea level (the level of the ocean's surface), plus or minus 10 feet (3 meters) because of snow. Mount Everest is in the Himalaya mountain range, on the border of Nepal and Tibet.
This height of Mount Everest was established by the Surveyor General of India in 1954 and accepted by the National Geographic Society. Prior to that the height was measured at 29,002 feet (8,840 meters). Satellite measurements taken in 1987 indicated that Mount Everest is 29,864 feet (9,102 meters) above sea level; however, this figure has not been adopted by the National Geographic Society.
The lowest point on land is the Dead Sea at 1,312 feet (399 meters) below sea level. The Dead Sea lies between Israel and Jordan. The lowest point on the Earth's surface (including land and sea) is thought to be in the Mariana Trench in the western Pacific Ocean, extending from southeast of Guam to the east side of the Mariana Islands. The Mariana Trench reaches a depth of approximately 36,200 feet (11,034 meters) below sea level.
Sources: Famighetti, Robert, ed. The World Almanac and Book of Facts 1995, p. 546; Ojakangas, Richard. Schaum's Outline of Theory and Problems of Introductory Geology, p. 5.