Looking at the figures, Mexico has, by far, the largest population of Spanish speakers, with about 107 million (at the time this data was collected). Next come Spain itself, Colombia, Argentina, and the U.S.
The U.S. Actually has more people who speak Spanish than Peru, Venezuela, or Chile! Since the U.S. Has a much higher population, even though it has about 34 million people who speak the language, it's use is not dominant, unlike the other nations on this list.
Also of note, is the fact that Spanish is not evenly spread throughout the country. For instance, 30% of residents in New Mexico speak Spanish, whereas it is very seldom used in other areas. It is more common in the Southwest region. Historically, that area was part of Mexico, and many people there are of Mexican descent.
All in all, Spanish is one of the most widely spoken languages in the world. It can be heard anywhere from Europe to America (North and South), and even certain parts of Africa and Asia that once had close ties to Spain.
