Kesselaid (also Kessulaid, or diminutively Kessu. German: Schildau; Swedish: Sköld, Skölldo) is a 1.7 km² (0.66 sq mi) Estonian islet located between the mainland and the island of Muhu in the Suur väin (Big Strait) which connects the Väinameri strait and the Gulf of Riga.