The federal income tax rates do not vary based upon zip code.
Short-term capital gain (capital assets held for one year or less) is taxed at your ordinary income tax rate.
Long-term capital gain (capital assets held for more than one year) is taxed at capital gain tax rates which are generally 0%, 15%, and 20% depending upon your taxable income.
See https://www.irs.gov/taxtopics/tc409
Note that if you are conducting this type of activity, flipping houses, with relative frequency and on a short-term basis, the IRS might consider this to be a business and the houses to be inventory. In that event, the gain would be considered ordinary income and subject to self-employment tax.
