Alonso is a Spanish name of Germanic origin that is a Castilian variant of Adalfuns. The original Visigothic name Alfonso suffered the phonetic change of the phoneme /f/ into the mute /h/ in the Early Middle Ages (around 9th Century), what eventually suppressed the sound /f/ from the name, deriving in the modern form Alonso. Due to the demographic particularities of the Iberian peninsula during the Middle Ages, this phonetic change was not uniform across the territory and the original form Alfonso also survived in different areas. Therefore, today both forms of the name coexist in Spanish speaking countries.

Geographical distribution

As of 2014, 36.6% of all known bearers of the surname Alonso were residents of Spain (frequency 1:222), 26.1% of Mexico (1:832), 8.3% of Cuba (1:242), 7.0% of Argentina (1:1,061), 4.8% of Brazil (1:7,502), 4.5% of the United States (1:14,083), 2.5% of Colombia (1:3,318), 1.7% of Paraguay (1:736), 1.3% of France (1:9,082) and 1.1% of Uruguay (1:549). In Spain, the frequency of the surname was higher than average (1:222) in the following regions:

First name

Surname