The original state flag of New Mexico, designed by the historian Ralph E. Twitchell and adopted in 1915, was typical of American vexillography (flag design). On a blue background it included the name of the state, its order of admission to the Union (47), the state seal, and a U.S. flag.
In contrast to most American state flags, the current New Mexico flag is starkly simple. The colours are based on the flag of Spain, which had ruled New Mexico until the early 19th century as part of the Viceroyalty of New Spain. The state flag was designed by the archaeologist and physician Harry Mera in a competition sponsored by the Daughters of the American Revolution. The flag was officially adopted in March 1925. Today the Zia sun is widely recognized as a state symbol, and the architectural design of the capitol building in Santa Fe was influenced by its shape.