I have lived in 3 states while working for the same company. One state has its own tax statement, but the other two are listed together in boxes 15-17 on my W-2 form. The income is not split between the two states... how do I break this down on each state's return? Thanks!

Any income earned while present in a state must be reported to the state.

One state may be your tax home. In the state that is not your tax home, report income you earned while in that state. If you have received only one W2 from your employer, then use simple arithmetic based on number of days spent in the state to figure our the income that you should report to this state.

In the state that is your tax home, report your worldwide income for full year. Also in this state claim credit for the taxes paid to the other state. Your U.S. Tax Return: Working or Living in Two or More states

Need some more detail here - what are the states, and did you happen to work in one state while living in another?