Moodus is a census-designated place (CDP) in East Haddam, a town in Middlesex County, Connecticut, United States. The population was 1,263 at the 2000 census.
According to the United States Census Bureau, the CDP has a total area of 2.9 square miles (7.5 km2), of which, 2.9 square miles (7.5 km2) of it is land and 0.04 square miles (0.1 km2) of it (0.69%) is water. Moodus is located within the Town of East Haddam.
The area is subject to earthquakes, with an intensity VI quake occurring in 1568, and numerous quakes being recorded from 1638 onwards. The largest earthquake recorded for Connecticut was an intensity VII quake on 16 May 1791 near Moodus.