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    by Thomson Reuters

Accounting Software Login

(QuickBooks Online)

Onvio Client Center

by Thomson Reuters
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Meet Our Team

Meet Our Team

Thomas C. Mangum, CPA


Thomas C. Mangum “Casey” became the principal of our firm in 2015. An experienced CPA, Casey has worked in the accounting industry for over 10 years advising clients in an array of taxation, accounting, and finance matters. Prior to acquiring Mangum & Associates, Casey spent seven years working for Ernst & Young, LLP in Boston and Los Angeles. While there he provided in depth financial due diligence on over 60 mergers/acquisitions ranging in size from $1 million to over $1 billon.

Casey graduated from Wake Forest University with a Bachelor’s degree in Finance and a Master’s degree in Accountancy. He is a member of the American Institute of Certified Public Accountants and Maine Society of Certified Public Accountants. In the local community, Casey serves on the finance committee of Oasis Free Clinics.

Casey and his wife, Stephanie, live in Portland with their son John. In his spare time Casey enjoys mountain biking, fishing, and hiking.

William H. Mangum


Bill Mangum founded our firm in 1971. With over 40 years of experience in personal and business tax preparation, financial planning, payroll, accounting, and retirement planning, Bill offers our clients a wealth of advice and expertise.  

Prior to founding Mangum & Associates, Bill was a pilot in the United States Navy. He graduated from Wake Forest University with a degree in Mathematics.  He is a board member of the Holbrook Community Foundation.

Bill and his wife, Paige, live in Harpswell. They have two sons, Gordon and Casey. Bill enjoys fishing, hunting, and boating in his spare time.

Linda LeClair

Office Manager

Linda has worked at Mangum & Associates since 2001. Her responsibilities include being the first point of contact for all clients, providing payroll and bill paying services to businesses and individuals, and management of the firm’s receivables, payables, and other operational functions.

Linda has always been in customer service. She worked for Mere Point OB/GYN for 12 years as a receptionist and scheduler. When her two boys were young she was a waitress at the Dolphin Marina in Harpswell, Maine.

Linda grew up in the area and attended Mt. Ararat High School in Topsham, Maine and the University of Maine Farmington. It was in college that she met her husband Gary. They have been married for 37 years. They have four grandchildren together, and every Saturday they come to “Memere’s” house!

Her interests include walking, singing in a band at church, biking, traveling, cooking, gardening, kayaking, golf and cross country skiing.

Joe Mendell

Staff Accountant

Joe joined our firm in 2018. His responsibilities include tax preparation for corporations, trusts, estates and individuals. Prior to joining our firm he has worked for five years in the accounting industry.

Joe earned his BS in Business Administration with a focus in Accounting at the University of Southern Maine. He is currently studying to become certified as an Enrolled Agent.

Joe is married and has two children. Outside of the office, Joe enjoys golf, traveling and spending time with his family.

Sara G. Stelk, EA

Staff Accountant

Sara joined our firm in 2019. Her responsibilities include Full Charge Bookkeeping, Individual and Corporate Tax Preparation, and Payroll Processing. Prior to joining our firm she worked at RHR Smith & Co., CPAs and Cummings Lamont & McNamee.

Sara earned her Bachelor’s degree in Theatre, Third World Studies, with a concentration in English at The University of the South (Sewanee). She received her Teacher Certification and her Certificate in Accounting from the University of Southern Maine.

Outside of the office, Sara enjoys spending time with family, gardening, puzzles and playing her cello.

Hilary Innis

Staff Accountant

Hilary has been with Mangum & Associates part-time since 2004. She provides bookkeeping and payroll services and has extensive QuickBooks experience.

Hilary splits her time between Mangum & Associates and another administrative office here in Brunswick. Her professional experience includes administration and bookkeeping in construction, non-profits, political organizations, and personal finance.

She enjoys gardening, hiking, kayaking, skiing, and spending time with family at their camps on the ocean and lakes.

Latest from Our Blog

Our New Website!

Mangum & Associates is excited to announce the recent launch of our firm’s new website. We’ve been working very hard to enhance our website and give our firm a fresh look. We’ve also continued to research and identify the latest and greatest technologies to improve the services we provide and ensure we continue to meet your needs.

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