Fernando García de Hita (or de Fita; floruit 1097–1125) was a Castilian nobleman, traditionally considered the founder of the noble House of Castro. He governed the lordships of Hita and Guadalajara, and frequently attended the royal court under King Alfonso VI and Queen Urraca.
"Fernando García de Hita" is a conventional name. Contemporary documents only record Fernando with his patronymic, which may also be spelled "Garcés" or "Garciaz" and indicates that his father's name was García. Fernando may have been an illegitimate son of King García II of Galicia. In one charter, Queen Urraca refers to Fernando as "our cousin, Sir Fernando García" (uobis annaia don Ferrando Garciez). In another, she refers to Fernando's second wife as "my cousin" (mea cogermana). The ancestries of both Urraca and Fernando's second wife are well known and they were not blood relations, the charters can only refer to a blood relation between Urraca and Fernando, best explained by Fernando's being the son of Urraca's uncle of the correct name: García of Galicia. In this case, Fernando would probably have been born to a mistress while García was in captivity.
Other evidence points to Fernando being the legitimate son of Count García Ordóñez de Nájera by Urraca Garcés of Navarre, Queen Urraca's kinswoman. The Muslim historian Ibn Abi Zar recorded that a "son of Count García" (Iben al-Zand Garsís) held the towns of Guadalajara and Hita.
In twelfth-century León and Castile, it was uncommon for the lords of the southern frontier—whose primary responsibility was defence against the Almoravids—to frequently attend the itinerant royal court. Fernando seems to have done both. He was given charge of several frontier fiefs (tenencias) and still managed to witness to twelve royal charters during the reign of Urraca. He was the royal official (alcalde) in charge of Guadalajara and Medinaceli in 1107. According to the Anonymous Chronicles of Sahagún, in 1111 Fernando convinced Count Henry of Portugal to break his alliance with King Alfonso I of Aragon and Navarre, and then negotiated a renewed alliance between Alfonso and Urraca after the latter distanced herself from Count Henry. The Historia Compostellana also refers to the aid a certain "Count Fernando" gave his relative, Queen Urraca, at this time, but historians are divided as to whether this is a reference to Fernando García de Hita, since there is no other evidence that he ever received the title of "count".