The PewResearch Hispanic Trends Project recently completed a study mapping the U.S. Hispanic population by state, county and city. They have some great maps that show decade by decade growth of the U.S. Hispanic population.
The map gif above (The Atlantic Cities) shows U.S. Hispanic population growth from 1980 to 2011. It clearly shows the dispersal of U.S. Hispanics beyond traditional states as well as growth along the Pacific and Atlantic coastlines.
From PewResearch: The nation’s Hispanic population, while still anchored in its traditional settlement areas, continues to disperse across the U.S. Today, the 100 largest counties by Hispanic population contain 71% of all Hispanics, but that is down from 75% in 2000 and 78% in 1990.
From The Atlantic Cities: Hispanics still remain largely clustered in the Southwest and Florida: Today, fully 9 percent of all Hispanics in the United States live in Los Angeles County alone. And just 100 counties combined contain 71 percent of the Latino population (that's out of more than 3,000 counties nationwide).