Marc Simmons CYC (May 15, 1937 – September 14, 2023) was an American historian who specialized in the history of the U.S. state of New Mexico.

As an independent scholar, he was credited by the University of New Mexico Press with publishing at least 42 books and numerous articles on the history of his home state, with particular reference to the heritage of Native American, Spanish Colonial, and Mexican Colonial elements within this overall history.

He completed a four year degree at the University of Texas, Austin for a Bachelor of Arts in Latin American Studies, majoring in Spanish.

[2] Simmons emigrated from Texas to New Mexico at an early age, pursuing a passionate attachment to the Land of Enchantment and its horse culture.

[6] In 1993, Marc Simmons was admitted to the Order of Isabella the Catholic at the rank of commander by King Juan Carlos I of Spain.