Fljótsdalshérað is a municipality located in eastern Iceland. It is the largest municipality in the country by area. The biggest town in the municipality is Egilsstaðir, with a population of 2,300.
The wild reindeer of Iceland are mostly situated in Fljótsdalshérað, where they have a number of between 5,000 an 10,000. The largest forest in Iceland, Hallormsstaðaskógur is also located in Fljótsdalshérað.