The off-road challenge started near Camp Filler, and had runners snaking their way through the nearby wooded area.
This hard core race contained more than 10 obstacles for runners, which is why you see many of them covered with mud.
And coordinators say they're ecstatic with the number participants who entered.
Clayton Hein, who's with Leadership Wichita Falls and was one of the organizers of the event, says, "I think we had a goal of about 500 at one time. We blew that out of the water. We're probably over 800 now, approaching 900... Maybe even into 1,000."
Proceeds from T.H.O.R. will benefit local charities and area first responders.