Since 1820, Mexico has been the fourth largest source of immigrants to the United States, and the number of Mexican immigrants is only increasing. If you are Mexican-born or have Mexican ancestors, consider yourself lucky. Unique surname traditions and widespread availability of church records make it easy to trace Mexican ancestry.
Understanding how surnames were passed down will help you in your search for ancestors. Traditionally, a child was given her father's surname followed by her mother's. For example, a child named Maria whose father's surname was Garcia and whose mother's surname was Sanchez would be named Maria de Garcia y Sanchez. In more recent times, her name would be listed as Maria Garcia Sanchez or Maria Garcia-Sanchez. Once Maria married, her name would change. If she married a man with the surname Gonzalez, she would become "Maria de Garcia y Sanchez de Gonzalez." This traditional surname inheritance is very helpful for researching your genealogy. If you have Mexican ancestry, you'll never face the common genealogical problem of having the trail going cold because you don't know an ancestor's maiden name. Be aware, however, that in recent years many family members may just to take their father's surname. When you are searching for individuals in the census and other records, search under their mother's surnames, father's surnames, and both surnames put together.
To find records of your Mexican ancestors, start by locating them in census records to find out approximately when they came to the United States. If they immigrated before about 1906, their immigration records can be found in the county where they settled, if the records exist at all. More recent immigrants filed with the U.S. Citizenship and Immigration Services, and you can write to the immigration office to obtain their records.
Vital records are easy to come by in Mexico. Local governments have been keeping these records since about 1857, and Catholic church records have been kept since the Spanish conquest. Catholic church records record christenings, marriages, and burials, and their accuracy and usefulness is unrivaled in the world of genealogy.
If you are fortunate enough to be able to cross the Atlantic and trace your genealogy back to the mother country, knowing the origin of your ancestral surname can help locate your ancestors in Spain. In early times, a Spanish surname was derived from one's father's name by adding "es" or "ez" on the end. For example, if your father's name was Alvaro, your surname would become Alvarez, and Gonzalo would become Gonzalez. Some Spanish surnames came from occupations; for example, "Molina" means miller. Some surnames come from regions in Spain, and these are especially useful in determining where your ancestors came from. The surname "Vasco," for instance, is a sure indication that your ancestors are from the Basque country in northern Spain.
If you know the basics, finding your Mexican ancestry is easy and fun. ¡Buena suerte!