Where is a One Country Pass valid?
An Interrail One Country Pass is only valid within the one country indicated on the Pass. You cannot use an Interrail One Country Pass to travel from another country to the country indicated on your Pass.
Example: A resident of the Netherlands picks an Interrail Spain Pass for their 3 week-long holiday in Spain. The Pass is valid for travel only in Spain, and cannot be used to travel from the Netherlands to Spain. Likewise, a resident of Spain cannot use an Interrail France Pass to travel in Spain as it is only valid in France.
Keep in mind that you cannot purchase a One Country Pass for your own country of residence.