William and Flora Hewlett Foundation — Country: United States

NoteThe Wikidata source explicitly lists 'country' as 'United States' in the statements section. The source is about the William and Flora Hewlett Foundation, which matches the claim's subject exactly. The foundation is described as an 'American private foundation' and is headquartered in Menlo Park (a city in California, United States), all of which corroborate the country designation.