Colleen Marnell Named to Building Design + Construction’s 40 Under 40 Class of 2025

We congratulate Colleen Marnell, PE, for being named to Building Design + Construction’s (BD+C) 40 Under 40 Class of 2025—a recognition celebrating rising leaders in the architecture, engineering, and construction industry. As one of the firm’s youngest regional leaders, Colleen is a testament to exceptional leadership and a pioneer of Kimley-Horn’s services in the solar industry.

Colleen led the launch and integration of solar engineering services across Kimley-Horn offices, expanding the firm’s solar practice into Virginia, Maryland, North Carolina, Minnesota, Georgia, and more. The results of her forward thinking have transformed Kimley-Horn’s energy footprint, leading to multi-million-dollar contracts in solar and natural gas services.

As someone whose passion for engineering began through education, Colleen is dedicated to mentoring the next generation of engineers through Kimley-Horn’s robust training programs. For the past 15 years, she has also volunteered at local high schools in her hometown of Chicago, sharing insights into the different career paths within engineering. In addition to her mentorship of young professionals in and out of Kimley-Horn, Colleen has led committees for Commercial Real Estate Women Chicago, Women of Renewable Industries and Sustainable Energy, Women’s Energy Network, and International Council of Shopping Centers Next Generation.

Colleen’s achievements exemplify outstanding leadership and a deep commitment to advancing the engineering profession for future generations, making her recognition from BD+C more than deserved.