Where Does Data Import Wizard Obtain the Country for the Country Field?

The Country column is a mandatory field and if it is not provided in your comma-separated values (CSV) file, Data Import Wizard tries to derive it from other sources. This action avoids any insert issues when, for example, the CSV file has a State column but no Country column. For the value, Data Import Wizard checks to see if the Default Country/Territory is specified in the State and Country/Territory Picklists. If a country is selected from the picklist, then Data Import Wizard uses that value for the Country. If a country is not selected, then the country selected in Signup Country Code during the org sign-up is used.