Tim Fritson, a track coach at Liberty High School, told 41 Action News he finished the marathon an hour before the blasts. He said the explosions occurred during a heavy-traffic time for the race.
"In that four-hour (mark) window ... there are a lot, a lot of runners coming in to the finish line," Fritson said.
Eladio Valdez III, with Runner's Edge in Shawnee, Kan., said around 40 runners from the club were in the marathon. He told 41 Action News he was able to track down all of them by 5:30 p.m., and confirmed they are all safe.
Three employees at Garry Gribble's Running Sports store were in the race, but store manager Steve Daley said all of them are safe.
Local runners took to Twitter to share their experiences and let loved ones know they're safe.
Early Monday evening, Ben Keefe tweeted: "My heart hurts right now, and I want to cry. Take a minute to pray for everyone at the Boston Marathon."
"I'm strong when it comes to hiding emotions in times of panic, but only now it has hit me. Holding back tears best I can," Ramsey Mohsen tweeted.
Another local runner, Ali Hatfield, tweeted that she felt the ground shake and heard the explosions. But she also recounted the kindness many runners experienced from locals after the blasts.
"There is love in this world. A sweet woman opened her home to us and gave us food, shelter and beer," Hatfield tweeted.
Runners who want to let family know they are safe can register on the American Red Cross' Safe and Well website. To register or check the list, go to http://bit.ly/9ZwlyY
The Red Cross does caution the site may be slow to load in the aftermath of the explosions.
You can also find out whether a runner finished the race by going to http://bit.ly/hDXDsd or by calling 617-635-4520.