St Marks Church
- Roman Catholic church, mass schedule, confessions, religious education, location and contact information.
- http://www.holycrossonline.net/Parish/StMark/

Harsens Island Lions Club
- Activity calendar, schedule of meetings, membership and contact information.
- http://harsensislandmi.lionwap.org/

Save Our South Channel Lights
- An all-volunteer, non profit organization that was formed to raise public awareness and support for the preservation and restoration of the Old South Channel Range Lights constructed in 1855. Membership information, image gallery, message board, fundraisi
- http://www.soschannellights.org/