Ibarra, Francisco de fränthēs´kō ᵺā ēbä´rä [key], 1539?–1575, Spanish conquistador in Mexico. In 1554, after founding Fresnillo , he headed an expedition to the N of Zacatecas. For the next 20 years he explored, founded settlements, and exploited mines in the vast region comprising present-day Durango, Chihuahua, and part of Sinaloa, which he called the Kingdom of Nueva Vizcaya. In 1562, after his most successful campaign, Ibarra was named governor, a post he retained until his death.
See study by J. L. Mecham (1927, repr. 1968).