I believe that every American state added people between the 2000 census and the 2010 census, but as this map from the Brookings Metropolitan program shows the picture is quite different if you look at the under-45 population:
This is basically a uniform trend. The regions that are adding under-45s are also experiencing the strongest population growth among over-45s, and all states are adding over-45s: “All states and metropolitan areas are showing noticeable growth in their older and ‘advanced middle age’ populations which, for the first time, comprise a majority of the nation’s voting-age population.” Interestingly, the highest median age state in America is not Florida — known for its senior citizens — but Maine, where 42.7 years is the median. Back in 1990, Florida was the oldest state. By 2000, it had been overtaken by West Virginia. But as of the 2010 census, New England leads the way with Maine followed by Vermont, then West Virginia, then New Hampshire, and then Florida.