Measurements of tropical cyclones (TCs) at landfall in their inner regions are limited. Typhoon York (9915) stroke Hong Kong directly at a typhoon-strength level in 1999, and resulted in the most severe TC-related disasters in the region since 1983. During the passage of York, the Hurricane Signal No.10, which is the highest level of TC warning signal in Hong Kong, had been hoisted for a record-breaking duration of 11 ​h. This article presents a comprehensive field study on this special typhoon, based on extensive in-situ measurements collected by radiosonde balloons, wind profilers and surface-based meteorological masts at various stations around Hong Kong. A number of interesting phenomena about the thermodynamic and kinematic characteristics in York’s inner region within its whole depth have been reported. Results presented in this study are expected to provide useful information for better understanding the inner structure of TCs at coastal areas.