Seyd Nour Alimardari, a local emergency aid official, said a 50-year-old woman was reported to be missing as floods wreaked havoc on Mehran County in the western Iranian province.
Search teams later found her dead body, he added.
Flooding has inflicted material damage on many affected areas of the province, with more rainfalls forecast for the days to come.
Weather officials had earlier issued warnings for heavy downpours and consequent flooding not just in Ilam, but in many other parts of the country, including the capital, Tehran.
Tehran and other areas in its vicinity have received ‘orange alert’ for flooding, with people advised to avoid riversides.