The state of South Dakota does not have an individual income tax. Other tax responsibilities may apply, such as business, property, special and motor fuel taxes. Information can be found at the South Dakota Department of Revenue http://dor.sd.gov/.
Taxes in America by 
From Optimal Tax Theory to Tax Policy by The Internal Revenue Service, a bureau of the Department of the Treasury, serves as the tax administrator for the United States.
The IRS Mission:
Provide America's taxpayers top quality service by helping them understand and meet their tax responsibilities and enforce the law with integrity and fairness to all.
The United States Congress passes tax laws and requires taxpayers to comply. The IRS role is to enforce the law while assisting taxpayers with the tax law with compliance.
Statutory Authority
Article 1, Section 8 of the Constitution of the United States grants Congress the "power to lay and collect taxes, duties, imposts and excises, to pay the debts and provide for the common defense and general welfare of the United States".
Federal tax law begins with the Internal Revenue Code (IRC), enacted by Congress in Title 26 of the United States Code (26 U.S.C.).
Federal tax forms for individuals and businesses can be found at http://www.irs.gov
The state of Wyoming does not have an individual or corporate income tax. Other taxes, such as excise, mineral and property taxes do apply. Information is available from the Wyoming Department of Revenue at http://revenue.wyo.gov/.
