黑矶市是位于栃木县北部的一市。2005年1月1日，与那须郡西那须野町，盐原町新设合并为那须盐原市。

Kuroiso(黒磯市,Kuroiso-shi) was a city located in Tochigi Prefecture, Japan. The city was founded on November 1, 1970.

As of 2003, the city had an estimated population of 60,145 and the density of 175.29 persons per km². The total area was 343.12 km².

On January 1, 2005, Kurioso, along with the towns of Nishinasuno and Shiobara (both from Nasu District), was merged to create the city of Nasushiobara.