The executive director of the Chicago Area Runner's Association, Wendy Jaehn, ran the Boston Marathon Monday morning along with roughly 974 Illinois runners who registered to participate.
The 2013 Boston Marathon ended abruptly, however, with explosions near the finish line.
Jaehn said a majority of the runners from Chicago have been located and accounted for.
The Boston Marathon web site offers a service that allows users to look up individual runners based on location of origin. Of the 974 Illinoisans who registered for the race, 361 hailed from within Chicago city limits.
"I don't think that anybody could have every fathomed that someone would think about doing this at a marathon," Jaehn said. "The timing that it went off, around the four hour mark of the marathon, that's really when the bulk of the runners start coming through with your average marathon finishing time, so it appears to have been designed for maximum impact and it's just sickening."
Jaehn's is at the airport waiting for a flight back to Chicago and using phone calls and social media to track down all the runners from the Chicago-land area.
NBCChicago.com was able to speak with a few.
Joey Cocco, 27 of Chicago, finished the race in 3 hours and 18 minutes and managed to cross the finish line before the explosions. He was already back to his hotel when the melee occurred and watched it unfold on the television.
Sara Parks, a Senior from Marquette University, ran the 26.2 mile course and finished in 3 hours and 14 minutes. Parks crossed the finish before the explosions, but saw the aftermath from her nearby hotel.
"It's so sad." she said. "Now I'm glad I finished. ... the amount of runners, elbow to elbow through the chutes ..."
Chicago Marathon Executive Director Carey Pinkowski was in Boston Monday morning and spoke to NBCChicago over the phone. He was at the airport heading back to Chicago.
"It's just amazing," Pinkowski said. "We're not sure exactly what happened but there were definitely two explosions and there were some injuries.
"[Chicago Marathon General Manager Mike Nishi] didn't know what that was at first, but it was concerning. As we do in Chicago, the Boston Marathon has a complete medical support at the finish line, so they were able to deploy medical personnel at the scene immediately. ... this is something that really sent -- wow, it's really emotional. Although it was at the ending of the race, there were still a lot of spectators in the area, people in the area, as a populated finish line is, but just -- very emotional by everyone. ... There are people here at the airport right now that had ran, that had friends that ran, so there's just a shock."
The medical director for the Chicago Race, George Chiampas, said he believes the Boston medical team acted on instinct.
At the moment when something like this occurs I think you just respond what you've been trained to do. After this, psychologically, I think a lot of people are going to need to kind of sit down and inhale and exhale and figure out what just occurred." he said. "Just like any city, every day that they wake up, they think about this, unfortunately since 9/11. The marathon is just like any other event that occurs, you wake up in the morning and you say, 'Hey, is our city safe? Is public safety in place?' and that's how we proceed with Chicago as, I'm sure, every other city."