Genealogy: 1870 Census birth year reference chart

census birth yearBy Barry J. Ewell
As you track your ancestor through the U.S. Federal Population Censuses, you can use age to help you

  • Identify individual members of the family
  • Provide clues to confirm I have the right person/family unit as you search each census
  • Provide clues as to relationship in the family
  • Provide clues if I have the right female when surnames change through marriage
  • Provide clues when people use nicknames and other name variations from one census to the next

I have prepared a birth year reference chart for each census to help you identify an estimated birth year for each ancestor.  This article will focus on the 1870 U.S. Federal Population Census.

Learn more about information about age found in the census:

1870 U.S. Census birth year reference chart
In Column 6 of the 1870 US Population Census, learn the age of each member of the household.  The following chart will provide the approximate corresponding birth year for the age provided.

Age calculated as of June 1, 1870.

AgeBirth YearAgeBirth YearAgeBirth Year
May 0/121870281842671803
Apr 1/121870291841681802
Mar 2/121870301840691801
Feb 3/121870311839701800
Jan 4/121870321838711799
Dec 5/121869331837721798
Nov 6/121869341836731797
Oct 7/121869351835741796
Sep 8/121869361834751795
Aug 9/121869371833761794
Jul 10/121869381832771793
Jun 11/121869391831781792
11869401830791791
21868411829801790
31867421828811789
41866431827821788
51865441826831787
61864451825841786
71863461824851785
81862471823861784
91861481822871783
101860491821881782
111859501820891781
121858511819901780
131857521818911779
141856531817921778
151855541816931777
161854551815941776
171853561814951775
181852571813961774
191851581812971773
201850591811981772
211849601810991771
2218486118091001770
2318476218081011769
2418466318071021768
2518456418061031767
2618446518051041766
2718436618041051765

Census taker instructions for age on 1870 Census
The following are the exact instructions given to census taker (enumerator):

Ages.-The exact age, in figures, will be inserted in column 4, wherever the same can be obtained; otherwise, the nearest approximation thereto. Where the age is a matter of considerable doubt, the assistant marshal may make a note to that effect. Children, who, on the 1st of June, 1870, were less than a year old, will have their age stated by the fractional part of the year, as (one month) 1-12, (three months) 3-12, (nine months) 9-12, etc. In all other cases, months will be omitted. The age taken is the age at last birthday.