Etymology and distribution of 貞常.

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

Ratio of 貞常.

カンマ区切りで複数の名字を指定できます。

Etymology of 貞常

Small area aggregation plots up top 5,000.

Exclude areas with less than about 20 corresponding surname.

Distribution of 貞常
Ranking
0 大阪府 大阪市西成区 千本中(Very rare / Very rare)
0 広島県 府中市 木野山町(Very rare / Very rare)