Hurricane Sandy made landfall on the East Coast of the United States around midnight UTC on October 30, 2012. What made this hurricane so devastating was the storm surge, which pushed water levels one to three meters above normal along the New Jersey and New York coasts. The radar altimeter on the HaiYang (“Ocean” in Chinese) 2A (HY-2A) satellite measured the size and offshore structure of the surge at its peak, across Long Island’s south shore. Significant wave heights measured by the altimeter reached almost 8 m near shore, and the combined effect of storm surge and high surf led to severe coastal inundation. The analysis presented here documents the largest storm surge signal to be captured by satellite altimetry to date, nearly 1.5 m, with validation provided by the nearby tide gauge at Montauk, NY.