Etymology and distribution of 老後.

Oigo 【老後】^{レベル3
About 200}  The Japanese surnames etymology dictionary.

Hiroshima-ken , Yamaguchi-ken , Oosaka-fu . Terrain . From Okinawa and Hara. There are examples where Oki means "back". Yamaguchi-ken Yanai-shi Yanai was on the Uema dish during the Edo period.

* Yamaguchi-ken Iwakuni-shi Yokoyama says that the Iwakuni clan of the Clan Office called Yamaguchi-ken Iwakuni-shi off the coast of Okiwa (Okihara) in 1871. Location unknown.

Rougo 【老後】^{レベル3
About 200}  The Japanese surnames etymology dictionary.

老後オイゴ参照。