Use 'kinsfolk' when referring to gatherings where many relatives come together, like reunions. We're having a large dinner with all our kinsfolk this Thanksgiving.
Pro Tip 2/3
Formal Tone
'Kinsfolk' has a formal or old-fashioned tone, often replaced by 'relatives' or 'family' in casual speech. She received an inheritance from her distant kinsfolk.
Pro Tip 3/3
Broad Connections
'Kinsfolk' implies a broad connection, which can include extended family and not just immediate relatives. His kinsfolk live in various countries around the world.