Here's the full list updated through post #62. If I can't identify the 2020 meet date, I'm using last year's date and extrapolating it to the same week of the season for this year. If any details in this post are incorrect, please post corrections in this thread, and I will update them here ASAP. For further clarification, please contact the host school or meet manager.
Preseason
8/15/2020 OHSAA Preseason Invitational
Week 1
8/24/2020 Ashtabula Lakeside War on the Shore
8/24/2020 Lost Creek Invitational - Limited to MVL teams only
8/24/2020 Springboro Opening Day Invitational
8/25/2020 Kent Trumbull Flashback Invitational
8/25/2020 Upper Sandusky Icebreaker
8/29/2020 Attica Seneca East Tiger Classic - Entry limited to teams in the immediate area
8/29/2020 Gates Mills Hawken Invitational
8/29/2020 GlenOak Golden Eagle Invitational
8/29/2020 Hunting Valley University School George Clements Invitational
8/29/2020 Sandusky St. Mary Panther Run to Fun
8/29/2020 Uniontown Green Bulldog Invitational
8/29/2020 Wilmington College HS XC Classic
Week 2
9/2/2020 Fairborn Skyhawk Cross Country Invitational
9/4/2020 BGSU Mel Brodt HS Invitational
9/5/2020 Avon Lake Early Bird Cross Country Invitational
9/5/2020 Greenville Treaty City Invitational - Limited to MVL teams only
9/5/2020 Miamisburg Invitational - Designated as "GWOC Only Meet #1"
9/5/2020 The Dual at the DeWines (Hosted by Thomas Worthington HS)
9/5/2020 Tontogany Otsego Invitational
Week 3
9/8/2020 Smithville Smithie Invitational
9/12/2020 Brecksville Bruce Lerch Invitational
9/12/2020 Dover Cross Country Invitational - Entry limited to local teams only
9/12/2020 East Palestine Rotary Invitational
9/12/2020 Tiffin Carnival - Entry limited to teams from local counties
9/12/2020 Troy Cross Country Invitational - Limited to MVL teams only
9/12/2020 Cuyahoga Falls Walsh Jesuit Pat Ritchie Invitational
9/12/2020 Springboro Invitational - Rescheduled for 9/19 and designated as "GWOC Meet #3"
9/12/2020 Warren Champion Ray Sweeney Invitational
9/12/2020 Wooster Cross Country Invitational
Week 4
9/16/2020 Cleves Taylor Invitational
9/19/2020 Beavercreek Invitational - Rescheduled for 9/26 and designated as "GWOC Meet #4"
9/19/2020 Cedarville Friendship Cross Country Invitational
9/19/2020 Cleveland VASJ McDonough Invitational
9/19/2020 Fayette Eagle Invitational
9/19/2020 Galion Cross Country Festival
9/19/2020 Tipp City Tippecanoe Dave Lightle Invitational - Limited to MVL teams only
Week 5
9/26/2020 Centerville Saturday Night Lights - Not sure if it'll still be run at night, but the meet is rescheduled for 10/3 and designated as "GWOC Meet #5"
9/26/2020 Malone Invitational (Malone might host a series of quad meets in its place)
9/26/2020 Niles Cross Country Invitational
9/26/2020 Oregon Cardinal Stritch Invitational
9/26/2020 Parma Hts. Valley Forge Patriot Invitational
9/26/2020 Rio Grande Patty Forgey Invitational
9/26/2020 Strongsville Vertical Runner Cross Country Invitational - 2 sessions of 8 teams each, and entry limited to teams w/ contracts from either Cuyahoga or an adjoining county.
9/26/2020 Todd Clark Cloverleaf Invitational
Week 6
9/30/2020 Glouster Trimble Burr Oak Open
10/2/2020 Gates Mills Gilmour Academy Paul Primeau Invitational
10/3/2020 Kettering Fairmont Neal Charske Firebird XC Invitational - Rescheduled for 9/12 and designated as "GWOC Meet #2"
10/3/2020 London Erin L. Nance Invitational
10/3/2020 Madison U Wanna Come Back Invitational
Week 7
10/7/2020 Thornville Sheridan Backwoods 2 Mile
10/7/2020 Tipp City Tippecanoe Tipp Relays - Limited to MVL teams only
10/10/2020 New London Dan Olien Cross Country Invitational
10/10/2020 Springfield/Northmont/Wayne Invitational - Designated as "GWOC Meet #6"
10/10/2020 Wayne-Holmes County Invitational
10/10/2020 Xenia Legacy Christian XC Invitational
Week 8
10/17/2020 Sim Earich Invitational
To those submitting info on cancelled meets, please include the meet's scheduled date if you know it. It makes it easier to maintain the list in chronological order which is probably the most important detail to everyone here right now. Also, this may not be the case too often, but please specify if a meet is only postponed and not cancelled. Obviously, the two terms have different meanings, so I'd like to keep confusion to a minimum here.
Thank you all for your help.