Seems to be either the Queen or Soldier butterfly.. they both look very similar. It is in the monarch family(pretty close the the bottom of the above webpage) Anyway, if you like butterflies this is a pretty informative page and I would think they would have one for each state.
Great pictures! I wish I had the patience to photograph them! We have some beautiful varieties in our restored prairie. Last week, the "butterfly de Jour" was black with a bright blue outline and tails.