Flag Pond is an unincorporated community in Unicoi County, Tennessee. It is part of the Johnson City Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined Statistical Area – commonly known as the "Tri-Cities" region.The community's name is believed to be derived from the presence of "flag flowers" growing in wet areas at the edge of a local pond. Flag Pond is the location of a post office, assigned ZIP code 37657.