Sans Souci Island is an island in the Cedar River in the city of Waterloo, Iowa. The island has a population of between 40 and 50 residents and is 100 acres (40 ha) in size, with most of the land area being woodland. The island was severely affected by the Iowa flood of 2008. By June 10, 2008 the island's entire population was forced to evacuate following the breach of a sandbag dike.