Prehistoric cultural affiliation(s) include Great Basin, Plateau and Shoshone dating back to 1499 BC.
The famous person Gov. John Morrison is associated with one of more of the Ada County historic places.
Some of the country's most noteable architects helped create the Ada County places including Tourtellotte & Hummel, Tourtellotte & Co., Wayland & Fennell, Campbell & Wayland, US Reclamation Service, US Army, A.J. Wiley and Christian Mittleider. Prominent architectural styles found in Ada Country are Queen Anne, Colonial Revival and Late 19th And 20th Century Revivals.