Circle Oaks is an unincorporated community in the hills to the northeast of the Napa Valley. Created in 1964, this wildland interface has thrived since, growing into a small country community outside of a bustling valley. Lots in the community are circular, with the areas between the circles ("triangles") considered to be non-developable "greenbelt", an idea supposedly envisioned by renowned architect Frank Lloyd Wright. The community was initially planned to have an airstrip and golf course, but these never materialized.

Circle Oaks was threatened, but not significantly damaged, by the 2017 Atlas Fire and the 2020 Hennessey Fire.