Tick Mark – Census Quick Reference Chart

The Tick Mark – Census Quick Reference Chart turns each age column of the 1790 to 1840 censuses into the range of years in which the people counted there were born. It lists the columns of each census in their original order, so a tick on a census page can be read as a range of possible birth years.

The federal census has been taken every ten years since 1790 to count the population for apportioning seats in the House of Representatives. Its questions collected demographic and other information for the government's use; the records they produced are also a major source for genealogical research.

The six sheets before 1850 name only the head of household; everyone else is a tally in age, sex, and status columns. 1790 divides the household five ways, and counts only free white males by age: 16 and over, or under 16. From 1800 the free white counts split into five age brackets for each sex, so a tally becomes a birth year range rather than adult-or-child. 1820 adds occupation counts and foreigners not naturalized, and counts enslaved and free colored persons by age for the first time. 1830 narrows the brackets into bands running past 100. 1840 adds pensioners for Revolutionary or military service by name and age — the only people besides the head named on these sheets — along with employment, school, and literacy counts. Each extraction worksheet carries its year’s own household columns in their original order; the 1840 school counts describe schools, not households, so that sheet leaves them out.

Each census counted ages as of its own census day: August 2, 1790; August 4, 1800; August 6, 1810; August 7, 1820; and June 1, 1830 and 1840. A tick places a birth within its range; to narrow it would require another record.

The first and last years of a range are partial: in 1830, someone under 10 was born after June 1, 1820, and someone 10 or older was born on or before June 1st of that same year. That is why neighboring ranges share a year.

The chart includes both ages at the ends of a range, so "10 to 15" means ages 10 through 15. The census wording was different. It wrote the same group as "of 10 and under 16." When the census used numbers, "to" meant "under." For example, the 1830 census's "10 to 24" means up to age 23, so the chart lists it as "10 to 23."

In 1820, free white males aged 16 and 17 were counted twice: once in column 3, and again in column 4 among those 16 to 25. Subtracting column 3 from column 4 gives the number of men aged 18 to 25, born 1794–1802. Column 3's tally is not added to the household's total, since those men are already counted in column 4.

The census gives no reason for the separate count. The likeliest is military: under the Militia Act of 1792, free white men became liable for militia service at 18, so the column counted those about to reach that age.

Each tick mark stands for one person, and the birth year range belongs to that person rather than to the household as a whole: three ticks in one column are three people, each born somewhere in that column's range. The one exception is 1820, when males aged 16 and 17 were counted in two columns at once, so their ticks appear twice; see The 1820 double count.

An identifier for a specific form. The same identifier goes on every page of the form, so pages that become separated can be put back together, and another form can refer to it.

The prefix is unique to each type of form. The rest, up to four characters, is chosen by the researcher and can be numbers, letters, or both. Combining letters with numbers allows more forms to be referenced with fewer characters. Each Quick Reference chart carries a fixed identifier instead, such as "QRC-C2", which names the chart itself and has nothing to fill in.

U.S. Census Bureau — census.gov

FamilySearch — familysearch.org

U.S. Government Publishing Office (GovInfo) — govinfo.gov