AbstractJupiter's magnetosphere is filled with plasma that expands from Io into an equatorial plasma disk, which preferentially inflates the magnetosphere against the solar wind equatorially. This results in a polar flattened magnetosphere and changes the dynamics between the solar wind and the magnetopause boundary. The degree of polar flattening at Jupiter, however, is not well known because no spacecraft has traversed the magnetopause at high latitudes. Instead, estimates must be made from much lower latitudes. In this study, we present a new method of estimating the large‐scale shape of magnetospheres by using magnetic field draping within the magnetosheath. Utilizing data of Jupiter's dawn magnetosheath from the Juno spacecraft, we estimate the ratio of the semimajor to semiminor axes of the Jupiter‐Sun‐North Y‐Z elliptical cross section of Jupiter's magnetopause is 1.29 ± 0.29.