Etymology and distribution of 佐久.

The Japanese surnames etymology dictionary.
https://play.google.com/store/apps/details?id=info.jigensha.jcedfreeGoogle Play で手に入れよう https://apps.apple.com/us/app/id1471109324
↑オフライン検索できるアプリもどうぞ
在日通名大全

日本初、在日通名の研究書「在日通名大全」発売中!
ネットの電話帳 住宅地図 マッポン!

「佐久」さんの名字の分布数。

カンマ区切りで複数の名字を指定できます。

Etymology of 佐久

Distribution of 佐久
Ranking
1 Nagano-ken(About 200)
2 Ibaraki-ken(About 120)
3 Toukyou-to(About 70)
4 Oosaka-fu(About 70)
5 Yamanashi-ken(About 30)
6 Niigata-ken(About 20)
6 Hokkaidou(About 20)
8 Kanagawa-ken(About 20)
8 Chiba-ken(About 20)
10 Hiroshima-ken(About 10)
10 Nara-ken(About 10)
10 Saitama-ken(About 10)
13 Shizuoka-ken(About 10)
13 Aomori-ken(About 10)
13 Aichi-ken(About 10)
13 Kyouto-fu(About 10)
17 Tottori-ken(Very rare)
17 Gunma-ken(Very rare)
17 Akita-ken(Very rare)
17 Fukushima-ken(Very rare)
17 Ishikawa-ken(Very rare)
17 Shiga-ken(Very rare)
17 Iwate-ken(Very rare)
17 Okayama-ken(Very rare)
17 Yamaguchi-ken(Very rare)
17 Hyougo-ken(Very rare)
17 Mie-ken(Very rare)