Stronghold Engineering, Inc. is an award-winning, Riverside, California-based construction firm in business for more than 25 years. Stronghold was founded in October 1991 as a small, electrical contracting firm. Through opportunity and the desire to live the American dream, Stronghold grew as a notable, go-to contractor throughout California and surrounding states. Due to the complexity of the projects and serving our customers with a partnering spirit, Stronghold has been able to achieve a 98% above average to outstanding performance rating. This is demonstrated by our more than 250 commendation letters written over the past 25 years.