William Gregory "Greg" Castanien passed away Monday, March 16, 2026, in his home. He was born on December 17, 1966, in Mansfield, OH to William J. and Marjorie Castanien. He attended school in Lexington, OH, Bowling Green, OH, and Defiance City Schools, before graduating from Lake Shore High School in St. Clair Shores, MI.

He loved the outdoors and had a desire to work as a Forest Ranger, which led to a year in the forestry program at Hocking Technical College. As a youth, his family spent as much time as possible at Mohican Forest, until they discovered Hocking Hills State Park and fell in love with the area. Greg enjoyed camping, fishing, hiking, and canoeing. He also had a passion for history and anything Native American. He spent many hours digging for arrowheads and artifacts in the fields around Defiance, acquiring a large collection. Greg worked several jobs in his life, including factory work, grave digging, a projectionist at a movie theatre, a job which he truly enjoyed and led to a love of movies and memorabilia, and finally Burger King.

In 2016, Greg married Kristin Adkins who survives. He and Kristin had a love for cats and enjoyed going to music concerts and movies. Greg suffered with his mental health, which despite continued treatment, became something that he was eventually unable to sustain and overcome.

Greg was preceded in death by his father, William J. Castanien, sister, Jo Marie Castanien, and brother, Jon Paul Castanien. He is survived by his wife, Kristin Castanien, his mother, Marjorie Castanien, his sisters, Carol Castanien-Bohn (Dave Peebles) of Florida, OH, and Barb Castanien of Defiance, his niece Angelique (Jeff) Bailey, nephews, Joe (Jenny) Bohn and Joshua Bohn. He was fond of his great nieces and nephews Liam, Aria, Rayla, Kendall, Jensen, and Finn.

Visitation will be held on Monday, March 23, 2026, from 6:00 pm - 8:00 pm and on Tuesday, March 24, 2026, from 9:00 am - 11:00 am at St. John United Church of Christ in Defiance. A funeral service will be at 11:00 am on Tuesday, March 24 at the church, with Rev. Janet Strickland officiating. A graveside service will take place at Oak Hill Cemetery in Upper Sandusky on Tuesday, March 24 at 2:45 pm. A reception will follow at Emanuel United Church of Christ in Upper Sandusky.

In lieu of flowers, the family asks that you might consider a donation in his name to the Ohio State Parks Foundation, or NAMI Four County.

To watch a recording of Greg's service: https://iplayerhd.com/player/video/0c0fc2f7-bf31-4748-bc74-7847dcf0df76/share