Federal income tax, administered by the Internal Revenue Service under the Internal Revenue Code, applies uniformly to all U.S. taxpayers regardless of state. Federal corporate tax, estate tax, gift tax, and payroll tax rules are identical across jurisdictions. IRS audits, Tax Court proceedings, and Appeals Office disputes operate under a single federal framework regardless of where your attorney practices.

State tax law adds a separate and highly variable layer. Income tax rates range from zero in Florida, Texas, and seven other states to above 13 percent in California. State corporate income tax, franchise tax, sales and use tax, property tax assessment procedures, and estate tax thresholds differ substantially by jurisdiction. Thirteen states and the District of Columbia impose their own estate tax — sometimes with thresholds far below the federal exemption — meaning some estates that owe nothing federally still face significant state tax liability.

Multistate businesses face apportionment, nexus, and transfer pricing questions that are entirely state-law-specific. Local taxes — city income taxes in New York, Philadelphia, and other municipalities — add yet another layer. A tax attorney who understands both the federal framework and your state's rules is essential for effective planning and dispute resolution. The state grid below links to tax attorneys in every jurisdiction.