Race records show at least 36 of 45 runners from Madison finished the Boston Marathon before two explosions shook the finish line, killing two and injuring at least 28.
Former State Rep. Steve Wieckert, a Republican from Appleton, finished the race minutes before the blasts.
He said he is okay and is staying overnight at a hotel near the finish line. He added a SWAT team remained in the hotel lobby on guard.
Abby Studinger, a University of Wisconsin-Madison junior and Marshfield native, participated in the marathon and narrowly missed seeing the explosion.
"We were just barely cleared out of the finish line area," Studinger said. "The explosion happened 20 minutes after I crossed the line."
Monday's race was Studinger's first time running the Boston Marathon. She said the experience will forever be foreshadowed by the blasts.
"You think about your first Boston Marathon being happy and a celebration, but it’s always going to be part of the memory for me, and for a lot of people," she said of the explosions.
Holly Hartung, a UW-Madison graduate, was watching the race and said she was less than a block from the second explosion when it happened.
"My only thought was, 'Run,'" Hartung said. "I didn’t even know if I was running in the right direction, but running felt like the right thing to do."
Hartung said she was walking into a department store when she felt the explosion. As she left, she said she witnessed confusion and fear in the streets.
"After I ran through the building I saw people in the streets. Some people looked confused as to why some people were running. Others were horrified, there were people screaming and crying, shouting out the names of people who I assumed they knew who were running," Hartung said.
Middleton native Greg Smith ran in the race and told WISC-TV he was taking the subway back to his hotel when reports of the explosion came through.
“We came out of the subway and we heard sirens nonstop for the last 30 minutes we were hanging around there, “ Smith recounted. “It was definitely something we’ve never been through before. It’s a very sad end to this day.”
Smith said city officials shut down all subway lines in the downtown area. He was able to return to his hotel via an outbound train.
Madison runner David Meixelsperger finished the race about 90 minutes before the explosion.
He sent an email to customers of his Madison running store and friends in the running community letting everyone know he was safe, but that he couldn't send or receive calls on his cellphone.
The fiance of Democratic state Sen. Chris Larson's brother also ran the race. Larson says Kristen Kamm finished 25 minutes before the explosion.
Larson says he saw his brother post on Facebook that they were both OK following the bombing. He later spoke with him by phone.
Larson says he's "very, very relieved."
According to the race website, hundreds of people from Wisconsin and at least 60 from the Madison area participated in the race.
The explosions took place just before 3 p.m. EDT, according to CNN reports. The race and subway service in the area were both halted.