Résumé
In 1823, George Everest was appointed as superintendent of the Indian Geodetic Survey. During his field campaigns in northern India, he noted that his gravity measurements led to a surprising conclusion: the Himalayan range is associated with a gravity anomaly that could only be explained by a mass deficiency. Since these first discoveries, the amount and quality of gravity measurements along the Himalayan range have continuously increased. This chapter provides a brief presentation of gravity methods and corrections, and details the main isostasy models. It shows how land gravity measurements are used to explain the mechanical support of the Himalayan topography, characterized by a spatial extension of ~2,500 km in length and peaks exceeding 8,000 m in altitude. Finally, the chapter presents the space gravity data acquired over the last two decades to extend the study areas associated with land measurements and to increase the depth of investigation.