A municipal bond is a debt obligation of a state, county, city, special district, or agency. Typically, interest on municipal bonds is exempt from federal income taxes and, if the bonds are issued in your state of residence, from state and, in some cases, local income taxes as well. Most municipal bonds are classified as either general obligation (G.O. bonds), which are secured by the property taxing authority of the issuing municipality, or revenue bonds, which only have recourse to the project revenues for which the bond proceeds are used.