Fernwood is a small unincorporated community in the southeastern corner of Benewah County, Idaho, United States, located just to the east of State Highway 3. The city shares a public K-6 school with the communities of Clarkia, Santa and Emida. All students attend high school and middle school in St. Maries.
The 2000 census recorded a population of 684 with an average household income of $27,578. The median age in the tabulation area is 41.2 and the average household size is 2.51.