General partnerships are treated as pass-through entities for federal income tax purposes. As a result, it makes little difference to the IRS as to which state the partnership is located (or "headquartered"); general partnerships are not taxed at the (entity) partnership level.
Some states require partnerships (even general partnerships) to be registered with the state and virtually all states require registration if the partnership will use an assumed name (aka a DBA).
Regardless, you might want to consult with local legal counsel if a formal partnership agreement is to be drafted.
