What state do I use for Capital Gains?

This seems rather complicated to me, but I hope it is not to someone else. My husband is in the military. Our home of record, and where we file our taxes, is Washington State. We own, and hope to soon sell, a house in North Carolina. We currently live in Maryland. Which state's laws apply to any capital gains we might have?

Any taxable gain from the sale of the house is taxable in North Carolina because gain from the sale of real property in a state is taxable by that state. The gain is also taxable in Washington, because you are Washington residents and all income of the residents of a state is taxable by that state. However, you get a credit against your Washington tax for the tax you pay North Carolina. You are not subject to Maryland tax on the sale because you and your husband are in Maryland on a temporary (military) basis.

That is about what I thought, though I did not know about it being taxable in Washington AND North Carolina. Washington State has no state tax, does this affect things? Or are Capital Gains something entirely seperate from state tax?

I'm sorry, I forgot about Washington not having a personal income tax. The capital gains are not separate from the state income tax; therefore, you do not have a Washington tax on the sale. The only state tax will be North Carolina.