It's the official start of the running season in Chicago and after the winter we just had, everyone was ready to get outside.
The sun was out, and the weather was perfect for a spring run.
"The weather was absolutely great," said runner Aaron Denning. "It was a little chilly in the morning but warmed up throughout the race."
"It's fantastic, I have spring fever now!" said runner Lori Ramsey.
After our harsh winter so many runners were just itching to start the outdoor racing season in Chicago.
"The treadmill's been daunting and boring, and a few runs have been very, very, very cold outside, but it's great to be out here today with the sun shining and the warmer weather," runner Tracy Wasilewski said.
This year's 35th annual Bank of America Shamrock Shuffle quickly reached its capacity of 40,000 registered runners. Some are doing it for the very first time.
"This is my first ever, 8K or any kind of K," Navjot Singh said. "It's my first run so I was pretty excited."
And others come back year after year, to perfect their personal records or to raise money for a personal cause.
Chicago Bears running back Matt Forte hosted "A Run For Our Future" for the first time here, benefiting his foundation.
"There's a lot of underprivileged youth, especially in Chicago, who have dropped out of high school, have contributed to the crime rate and so if I can continue to raise money and donate to those scholarships to those kids where they can graduate high school, and encourage them to do that and go to college or a trade school and see them through," Forte said.
The 8K is an annual tradition that leads into the Chicago Marathon in October.