The flag of the State ofis, like most current Mexican state flags, the coat of arms centred on a white field.
The Coat of Arms of the state is a representation of a legend in the Conquest of Mexico by the Spanish Crown. According to the legend, while the Spaniards held a battle against the natives in the region, a solar eclipse took place. During the time it lasted, the Patron Saint of Spain () and the showed up.
The shield was given by the Spanish Crown to the City ofin 1665 and it's divided into three sections. The top one contains the darkened Sun crowned by a cross, over the night sky there's also two stars on the top corners. This section represents the eclipse in which the and the cross showed up. On the lower right section there's an image of the apostle, wearing military clothing and mounted on a white horse. The apostle is wielding a sword with one hand and with the other is holding the banner of the Spanish Royalty. On the lower left section there's a grapevine and some ears of wheat, which represent the fertility of the Queretan soil.
After the independence of Mexico, the Coat of Arms and the Flag of Mexico was added to the Coat of Arms of the State. On the lower part symbols of war such as cannons, bullets and arrows were added. They represent the importance of Querétaro in the military history of Mexico, specially the resistance against the .