ENR 2025 Top 20 Under 40
Colleen Marnell: Spearheads Expansive Growth of Midwest Region
Colleen Marnell
Photo by Bruce Buckley for ENR
Back To:
ENR 2025 Top 20 Under 40
Colleen Marnell
38, Midwest regional leader and senior vice president
Kimley-Horn
Chicago
Colleen Marnell was, as of January 2024, the youngest and third female regional leader in the history of Kimley-Horn. She got her start after graduating from the University of Notre Dame in 2008, joining the firm’s small development services team in Chicago, where she created computer-aided design standards, improved project structures and implemented tools to streamline workflows.
Marnell says one of her proudest memories is working on the North Star Solar project in Minnesota, then the largest in the Midwest. She relished the opportunity to work in a field “still in its infancy” without many rules and regulations. “We really got to use our engineering judgement, our critical thinking brain,” she says. “The team really came together to leverage everyone’s collective experience to come up with something that was going to serve the community well, as well as our client.”
The impact of Marnell’s leadership is evident in Midwest region growth from 2017 to 2023, while she served in various leadership roles. Its job starts grew from $70 million to $240 million, the number of offices expanded and more than 10 new service areas were established. She credits this success to people around her.
“It really comes down to all the people I’ve had the opportunity to work with,” Marnell says. “I think about internships I had and people who invested in explaining the why. I think about opportunities given to me when people believed in me before I believed in myself. It’s the summation of that investment in me ... that led to me being able to do things that I’ve been able to do.”
Today, Marnell oversees more than 800 employees and numerous functional groups, including human resources, information technology and finance.
As for how she sees the industry’s future, Marnell names the shortfall in engineers as one of the biggest challenges: “When you look at data coming out of colleges, you see we are not graduating enough civil engineers to keep up with demands of the industry.”
Looking for quick answers on construction and engineering topics?
Try Ask ENR, our new smart AI search tool.
Ask ENR →
The answer is for the industry to broaden its focus to hire not just civil engineers, but “problem solvers.” she says. "That’s what our business is all about. How can we apply those folks and teach them this industry?”
This new approach could fit with a changing industry as well.
“A lot of our clients’ needs are evolving,” Marnell says. “They are looking for more program management, things that you don’t need an engineering degree to do.”
More young women must be encouraged to pursue careers in STEM, the executive believes. She collaborates with her father, a high school chemistry teacher and adviser to the Society of Women in Engineering, Entrepreneurship and Technology, to inspire young women to explore relatedcareers.
