In 1850, the majority of American immigrants were from European countries. The Eastern seaboard was dominated by Irish immigrants, while Germans flocked to the Midwest and Texas.
By 1900, Germany had become the dominant source of immigrants to the US, while Mexicans started to move en masse into Texas and southwestern states like New Mexico and Arizona. In the north, Canadians began to move in large numbers to Maine, Montana, Wisconsin, and Washington.
In 1950, following World War II and the closing of the Iron Curtain, German immigration continued into the Midwest, while Russians began to show up in large numbers in Colorado, Oklahoma, and Tennessee. Immigrants from the UK became a major force in Southern states.
In 2010, Mexico became by far the most dominant source of immigrants to the U.S., outpacing all other source countries in the majority of states.
See the map below from Pew.