If you die without a Will in Massachusetts, the Intestacy Laws of Massachusetts will determine who inherits your assets.
If you die without a Will, you were set to have died interstate and that can be what your intent was for your assets; or your estate to go to. However, you are leaving that up to the laws of Massachusetts and the cost of doing a Will is very minor and you can put down exactly where you want your assets to go, rather than having the state decide.
