How to derive Region from City in sql

Question

I am required to create a new column 'Region'.

I have City (there are multiple cities in the list), County (multiple counties) and State columns available in the source table.

Is there a way to do so in SQL?

Thanks in advance for your kind support.

Here is a sample select statement:

Proc sql;

Create table test_region as 
  select full name, address, city, state, zip from details
...;
quit;