Internal Revenue Service, also known as IRS, is a bureau of the United States Department of the Treasury with headquarters in Washington, D.C. Established in 1862, it collects taxes, enforces the internal revenue laws and assists taxpayers. IRS has various divisions and principal offices, including wage and investment, tax exempt and government entities, office of chief counsel, advocate service, criminal investigation, appeals, and communications and liaison. Its tax exempt and government entities division serves local community organizations, municipalities, major universities, pension funds, state governments, Indian tribal governments and participants of complex tax-exempt bond transactions. Its criminal investigation office investigates potential criminal violations of the Internal Revenue Code and related financial crimes. The bureau s taxpayer advocate service division helps taxpayers to resolve their problems with the IRS and recommends changes to prevent the problems.