In the beginning, many areas collected poll (head) taxes or tithes on each adult male when he reached a certain age--usually 21, but sometimes 16 or 18 years--until he reached the 50- to 60-year age limit. Veterans, paupers, ministers, and some others were exempt. In some colonies, taxes, called quitrents, were collected on land holdings and were paid to proprietors, or to the Crown. These were abolished during the Revolutionary War because they were viewed as a holdover of the feudal bondage system. Later, taxes were usually based on real property (land) or personal property (especially livestock). These taxes took many forms and changed from year to year even in the same place. Several direct taxes were also levied by the federal government to raise money for wars, e.g. in 1798 for a possible French War; in 1814-16 for the War of 1812; in 1862-66 for the Civil War; and at various other times until 1917 when personal income taxes and other taxes were instituted by the federal government.

In general, each state had jurisdiction over what was to be taxed and how often the tax was to be collected. Except in New England, where town clerks kept the records, either the county or the state was the caretaker of the records collected by the various militia captains, constables, justices of the peace, or town clerks. Thus, some records were begun earlier than others, are more continuous than others, or are better and more available than others. Whenever available, tax records should be carefully scrutinized, as they can help not only to provide a better picture of a family's financial standing in the community but also to solve stubborn genealogical problems which may have no other proof.

If a man lived in the same community throughout his life, a researcher can follow him through the tax records from the time he came of age. His children's birth dates can often be estimated by the year when they begin to show up in the tax records. A wife's name may be found by comparing the disappearance of a man and subsequent appearance of a woman of the same surname with a similar number of taxed items. A father's name may be linked to a known ancestor if the son first shows up as "Jr." if the father paid taxes for a son (as was sometimes the case in areas which taxed individuals beginning at age 16), or if the surname is unusual and the only one in the area. When several people of the same name are found in the same area, tax records may help to link a child to the correct father, as they sometimes show how many children between the ages of five and 16 (school age) or males of 16 to 21 were in the household; the appearance of a young male next to one of the men suggests that they are father and son.

When moves from one area to another make it difficult to prove kinship, tax records may provide circumstantial evidence, if a person shows up in the records of one place for several years, and then disappears and shows up in the records of another place. In some cases, such as in Kentucky in 1790 and in Texas in 1840, tax records have been used as a partial substitute for lost census records. They also may be among the few surviving records in those Southern states in which many records were burned during the Civil War, as copies of tax records were often sent to the state capitals.

The researcher should be aware of some omissions of taxed persons. Whenever possible, look at the original lists as received by the clerk; these often contained names of others, including some children, living with the head of the household who were omitted from the final county lists. In general, children, slaves, and indentured servants were not named. Landless men over the poll tax age, paupers, ministers, justices of the peace, militia officers, and tax assessors were usually excused from paying taxes. A state could also grant exemption for any other reason it decided.