I don't think any State offers deduction for interests. But for your federal income tax purpose, there is no impact at all. You can still claim interest expense. Even if you buy another home in 明州, you can still claim interest expenses for both houses.
There is one situation that you can keep in mind in relation to capital gain. If you have two houses (no matter which states they are in), only one can be your primary home, for which there is a $500,000 exclusion for capital gain when you sell it (5 year holding period). That exclusion does not apply to your secondary home.
There is one situation that you can keep in mind in relation to capital gain. If you have two houses (no matter which states they are in), only one can be your primary home, for which there is a $500,000 exclusion for capital gain when you sell it (5 year holding period). That exclusion does not apply to your secondary home.