International Mountain Day rachel_thecat, CC BY-SA 2.0, via Wikimedia Commons International Mountain Day celebrates the beautiful landscapes of mountains all over the world and the journeys people have taken on them. National Mountain Day + Add to Google Calendar + iCal / Outlook export Date Dec 11 2025 Time All Day Local Time Timezone: America/New_York Date: Dec 11 2025 Time: All Day Category Holiday Share this event
