This code system http://hl7.org/fhir/measurereport-stratifier-value-example defines the following codes:

Code Display Definition
northwest Northwest Northwest region stratification.
northeast Northeast Northeast region stratification.
southwest Soutwest Soutwest region stratification.
southeast Southeast Southeast region stratification.
<status value="active"/> <experimental value="true"/> <publisher value="Clinical Quality Information Workgroup"/> <description value="Example Region Value Measure Groups for the Measure Resource."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <caseSensitive value="true"/> <valueSet value="http://hl7.org/fhir/ValueSet/measurereport-stratifier-value-example"/> <content value="complete"/> <concept> <code value="northwest"/> <display value="Northwest"/> <definition value="Northwest region stratification."/> </concept> <concept> <code value="northeast"/> <display value="Northeast"/> <definition value="Northeast region stratification."/> </concept> <concept> <code value="southwest"/> <display value="Soutwest"/> <definition value="Soutwest region stratification."/> </concept> <concept> <code value="southeast"/> <display value="Southeast"/> <definition value="Southeast region stratification."/> </concept> </CodeSystem>