The 99th district has been based in Ashtabula, Ohio since 1966 and now comprises most of Ashtabula County including Ashtabula, Conneaut, Geneva, Geneva-on-the-Lake, Jefferson, North Kingsville, Roaming Shores and Rock Creek, and portions of Geauga County including Aquilla and Chardon.
It makes up one-third of the 32nd Senate District.