Earth Day Hike Calendar Add to Calendar Add to Timely Calendar Add to Google Add to Outlook Add to Apple Calendar Add to other calendar Export to XML When: April 22, 2021 – April 25, 2021 all-day 2021-04-22T00:00:00-05:00 2021-04-26T00:00:00-05:00 Contact: Fort Abraham Lincoln State Park Event website City of Mandan General Community Morton County This is a bonus hike in the 2021 12 Months 12 Hikes Challenge.