YoungMulla wrote:I think it refers to where you grew up at, with the assumption that your parents had a permanent residence (read "home").
No, it should be where your parents/grandparents hail from. Thus someone who was born and brought up in Kahawa Sukari in Ruiru district, Kiambu county but whose parents are from Kianjokoma in Embu county will have Embu as his home county even though he can't say 'avai'.