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Meet the Staff

Diana Theall

Diana Theall, IOM

President and CEO

Secretary of the Board of Directors


Diana joined Team Denison in October 2018.  Diana's passion for the chamber industry and a strong belief in the mission of chambers, their involvement in the community and their support of local businesses has helped her build the Denison Chamber as one of the strongest and most impactful chambers in Texoma.

Diana has increased membership and revenue for the Denison Area Chamber of Commerce, enhanced existing programs and put in place new initiatives and programs to help grow and strengthen the Denison Chamber in the area.  Through her leadership she has helped create a strong and active board of directors who develop and guide the initiatives and directives of the Chamber.

Diana attended Texas Tech University, earned her Chamber of Commerce Excellence Certification (CCCE) from the Texas Chamber of Commerce in 2017, and earned her IOM certification in June 2022 from the US Chamber of Commerce Institute for Organization Management, earning the equivalent of a PHD in Non-Profit Management.

She is married to her high school sweetheart Bryan for 37 years and they enjoy fishing on Lake Texoma anytime they can. They have one daughter, Kirsten, son-in-law firefighter Chris Garcia and grandson, Dean, the cutest little redhead ever!  She has the best day when members drop by just to visit and share a cup of coffee and chat.


Chelsey Cook

Director of Events and Marketing


Chelsey, a proud Denison native raised in Southern Oklahoma, is a dynamic professional with a deep-rooted passion for communications, community engagement and brand development. Graduating from Southeastern Oklahoma State University in 2017, she earned a Bachelor of Arts degree in Communications with a specialized focus on Public Relations and Advertising. During her collegiate years, Chelsey was an active member of the Tri Sigma National Sorority, where she developed her leadership skills and commitment to service.

Embracing her roots in the Red River/Lake Texoma region, Chelsey became a part of the Denison Chamber in April 2021, a pivotal move that aligned her career with her talents and interests. As a dedicated team member of the Chamber, Chelsey plays an important role in orchestrating events, ensuring seamless operations and unforgettable experiences for members. Her strategic approach to marketing has been instrumental in elevating the Chamber's brand identity.

One of the moments that truly excites Chelsey at work is when members share high-resolution flyers and logos, a testament to her attention to detail and appreciation for visual aesthetics. Her ability to transform ideas into captivating visual representations not only enhances the Chamber's promotional materials but also reflects her creative flair and commitment to excellence.

Beyond her professional endeavors, Chelsey finds joy in the serene beauty of the Oklahoma ranch she shares with her husband, Zack. A lover of nature, Chelsey's days are brightened by her playful beloved dogs, the gentle presence of cows grazing in the fields, and the vibrant colors of blooming flowers in her surroundings.

Chelsey's journey as the Director of Events and Marketing at the Denison Chamber is a testament to her unwavering commitment to community, creativity, and collaboration. With a heart firmly rooted in her Texoma heritage and a vision set on shaping a brighter future for her community, Chelsey continues to inspire and uplift those around her with her infectious enthusiasm and dedication to making a difference

A New Design (1)

Susan Hamilton

Director of Membership and Outreach


Susan Hamilton is a seasoned professional with a diverse background, hailing from McKinney, Texas, and raised in Grayson County, Texas. Her educational journey commenced at Grayson College before she pursued her bachelor's degree at Texas State University. Seeking broader horizons, Susan ventured to the University of Hawaii at Manoa for her final year of studies.

Throughout her career, Susan has exhibited remarkable dedication and leadership skills. She spent a decade at Texas Instruments, where she ascended to the role of Supervisor, overseeing operations with finesse and precision. Following her tenure at Texas Instruments, Susan transitioned to KXII, where she spent 7 and a half years in sales, assisting businesses in crafting effective marketing strategies and implementing impactful television and digital campaigns.

In her leisure time, Susan enjoys creative pursuits, particularly filmmaking, where she channels her imagination and storytelling prowess.

Susan's personal life is as fulfilling as her professional and community engagements. She celebrates 21 years of marriage, sharing her life with a supportive partner. Together, they cherish their blended family, which includes a beloved step-son.  

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