How long is a generation?

Much of my attention over the last eighteen months has been focused on creating the online database Mayflower Families Fifth Generation Descendants, 1700-1880. It was great to make this resource available to help people research their Mayflower ancestry.

Now we have a database with nearly 165,000 birth, marriage, and death records, and thus a unique opportunity to do some analysis on the Mayflower fifth generation descendants in aggregate, looking for interesting facts about this group.

Determining just how long a period the fifth generation spans seems like a good place to start. So I crunched the numbers in an Excel spreadsheet for the 6,478 people with a birth year, representing about 92% of this generation. The chart above shows the distribution people born by year. The average birth year of the fifth generation is between 1725 and 1726, which is about 105 years after the Mayflower passengers arrived. For additional perspective I added red lines showing the range where 80% of the births occurred; this is between 1698 and 1757 – a 59-year span.

[The] outliers are remarkable, ranging from 1667 to 1795, for a 128-year time span.

This result does not does seem to be an extremely large range, but the outliers are remarkable, ranging from 1667 to 1795, for a 128-year time span. I found it surprising that first two members of the generation were born only 47 years after the Mayflower landed in 1620. Fearing that there might be an issue with indexing, I looked into the details of the first and last arrivals.

Rebecca Burge/Burgess (Patience Freeman4, Rebecca Prence3, Patience Brewster2, William Brewster1) came first, born 17 January 1667 in Sandwich, Massachusetts. William Brewster was born about 1566, which of course means that he was about 54 when the Mayflower landed. With this background we can see that the generations were not unusually close together. Rather, William Brewster was simply not a young man when the Mayflower sailed, and seven years after his arrival he was already a grandfather. Aside from having a head start, the people in this line averaged about 25 years old when their descendant was born:

  • William Brewster, b. 1566
  • Patience Brewster, b. 1600 (father was 34)
  • Rebecca Prence, b. 1627 (mother was 27)
  • Patience Freeman, b. 1647 (mother was 20)
  • Rebecca Burge, b. 1667 (mother was 20)

Gilbert Palmer Doty (Elias Doty4, Samuel Doty3, Isaac Doty2, Edward Doty1) was at the extreme end of the group. He was born 1 October 1798 in Clinton, New York. Edward Doty was a reasonably young passenger, having been born about 1599. However, the men in this line averaged nearly fifty years of age when their child was born:

  • Edward, b. 1599
  • Isaac, b. 1649 (father was 49)
  • Samuel, b. 1689 (father was 40)
  • Elias, b. 1732 (father was 43)
  • Gilbert Palmer, b. 1798 (father was 66!)

I am sure that many of us have noted a lot of variability in the birth years for a generation in any family. It is interesting to see just how wide the dispersion is for the fifth-generation descendants of the Mayflower passengers. William Brewster’s fourth-generation descendant Patience Freeman arrived just two years before Edward Doty’s second-generation son!

Additional notes for the statistically inclined: For this article I have included only the fifth-generation descendants included in the Silver Books (not their spouses or children), and of these people, only the ones with a birth date. Some additional points to consider: First, this is not actually the entire fifth generation, but rather the members of that generation who married and had at least one child. Second, it includes only the current Silver Books, so not the Soule “pink books” or the Howland books by Picton Press. And, third, there will be some amount of duplication due to intermarriage between lines. Despite these limitations, I think we still get some interesting perspectives about this group.

About Don LeClair

Don is the Associate Director, Database Search & Systems, at NEHGS. He first got involved with genealogy while in college and spent many a day in the NEHGS library tracing his ancestors through New England and New York. Don also did volunteer indexing work for the library before joining the staff in 2016. Previously, Don had a 30-year career in the software industry working in and leading engineering and product management teams focused on IT Management products. Don has a B.A. and M.B.A. from Boston University.

24 thoughts on “How long is a generation?

  1. Are there any plans to make the Howland information from the Picton Press books available? I am descended from daughter Hope, and those seem to be the only books that document her, other than Mayflower Births and Deaths.

    1. Unfortunately, we do not have the rights to publish the Picton books. However, there is another project underway with the GSMD to index and publish Mayflower Society Applications for people born more than 100 years ago. This will include all Mayflower lines including all of Howland and Soule. We don’t have a formal date yet, but plan to have it before the 2020 anniversary.

        1. Hi Lisa – yes the Picton Press “blue books” are available in the 7th floor reading room at NEHGS, and probably can be found in other libraries as well.

        2. Snippet views of “John Howland … Vol. 3 … through … Hope …” are available in Google Books. See

          According to the Mayflower Society, Vols 1-4 (through Desire, through John, through Hope, and through Elizabeth) are all “out of print and not expected to be reprinted” (see

          Perhaps another publisher will make a deal with the inheritors of Picton Press to reprint these books.

          These four John Howland volumes are available in the NEHGS library, see

          Here is a synopsis of the table of contents of the Hope volume in case anyone wants to request a “fair use” portion of the book from a library:
          1st gen. John Howland and his wife, Elizabeth Tilley, 17-28
          2nd gen. Hope Howland, wife of John Chipman, 29-35
          3rd gen. The children of Hope Howland, wife of John Chipman, 37-57
          4th gen. the children of the following:
          Elizabeth Chipman and Hosea Joyce, 59-71
          Hope Chipman and (1) John Huckins, (2) Jonathan Cobb, 71-91
          Lydia Chipman and John Sergeant, 91-103
          Hannah Chipman and Thomas Huckins, 103-111
          Samuel Chipman and Sarah Cobb, 111-130
          Ruth Chipman and Eleazer Crocker, 130-141
          Bethiah Chipman and (1) ___ Gale, (2) Timothy Dimmock, 141-145
          Mercy Chipman and Nathan Skiffe, 146-150
          John Chipman and (1) Mary Skiffe and (2) Elizabeth Handley, 150-173
          Desire Chipman and Melatiah Bourne, 173-181
          5th gen. the grandchildren of each of the above, with sections starting on pages 183, 243, 329, 352, 363, 433, 485, 497, 511, and 584
          Every Name Index, 617-672

    2. Hi Maria,

      I have the daughter Hope book. If there is something you’d like for me to look up for you, let me know.

      There are more than 400 descendants in the fifth generation listed in the daughter Hope book. I took a quick look at their birth years. The earliest I saw was 1691 and the latest was 1784. (Handley Chipman was almost 67 when his last child was born.)

      In the daughter Hope book the fifth generation is counted with John Howland and Elizabeth Tilley as generation 1. I suppose one could start the count with Elizabeth’s parents who were also passengers on the Mayflower. In that case, the fifth generation birth years would range from 1671 to 1719.

      1. Suggestion if I may. When you select print do so as a pdf file (like Adobe) and save it to your computer desktop. Once save that way you should be able to easily print it.

  2. I’m waiting for the next generation. That’s the one my grandma is in. Harriet Newell Cooke, daughter of Manassah Cooke married Daniel D. Ward of Halifax. That is every bit of information I know about Daniel other than he married his first wife, Margaret Full, in 1836 she died in 1839. He married Harriet about 1840. Was Charles DeWolfe Ward Margaret’s son or Harriet’s son? Daniel is my brick wall. From DNA I know that he descends from George and Elizabeth Doggett Ward. I need the bridge from that line to Daniel. The Canada father’s will is out there somewhere, I hope. If not that, then something, anything, to help me find him.

  3. Love this post! I’ve kept an eye on generations as I’ve worked on my tree. I have one ancestor who was a father at close to 80 (third wife, he wore the other two out!) and one who was a father at 19. Different lines seem to have different spacings for children, too, and I’ve wondered why that would be. It’s lead to some interesting discoveries.

  4. Fascinating exercise – and the line with the older men really underscores the range. My grandmother was nearly 40 when my mother was born, and my mother was 32 when I came along, the same as I was when my son was born. So there are just 3 generations of us in a century, definitely on the older end. I have friends who are more in the 5-generations-to-a-century range. So within that same century, they are far more likely to know their grandparents, or even great-grandparents. I hope they’re taking advantage of that, for genealogy’s sake.

  5. Don – when I ask to have the graph/picture printed, nothing is printed, similar to when I have the column printed

    1. Hi Howland, It prints correctly for me, using either Chrome or Edge as the browser on Windows 10. You could try clicking on the graph to display the larger version, which is a jpg file. Then you could save the jpg file to your computer and then print it.

  6. I also think during the time of the Revolutionary War, generational lines get blurred as well.
    With a seven year span when men were back and forth at home, the gaps between children and second families gets bigger. Many of the men I”ve traced who were militia men married much younger women after the war and basically started separate families. Gets really confusing to determine who is a child versus a brother or sister of the militia man.

  7. Very nice job! One could argue, though, that Rebecca Burge(ss) is not an outlier. Patience Brewster was not born as a child of a Mayflower passenger. She was born 20 years earlier, and she wasn’t even on the Mayflower.
    What’s the answer to the average length of a generation? By smoothing the curve, it appears that a generation during that time was about 100/4 = 25 years. That’s a nice round number I often see in print.
    Today, people seem to be delaying marriage and birthing.
    There’s nothing to be gained by niggling about your additional notes. Statistics can drive a person mad. I used to remind my university students that the average American has two nipples and one testicle, but a typical American does not!

  8. Very intriguing! I thought it would be interesting to do a different kind of “demographic” study and see how widespread the first and last born (and died) of my ancestors in each generation were. Differences in age of my parents: 4 months, 8 days, grandparents, 14+ years, great-grandparents: 23+ years, great-great-grandparents 39+ years and great-great-great-grandparents 49+ years. At that point the project came to a close thanks to all the unknown ancestors in earlier generations.

  9. My paternal line is certainly in the outlier category: my father was born in 1894; grandfather was born in 1852; and g.grandfather was born in 1812 (i.e. 206 years ago—during the first term of the presidency of James Monroe). Knowledge of this chronological span of this line of my family, in particular, has definitely influenced my perspective on and interest in American history. Basically, it can be described as the “youngest son of the youngest son” syndrome, resulting regularly in substantial “generational slippage.” For a single-generation example, my eldest 1st cousin (born 1914), married the same year I was born (1936) so, although her children were my immediate contemporaries age-wise, they were actually my 1st cousins, once removed.

    1. Richard. I’m in the same position. My grandfather was born in 1865, six months after the Civil War ended. My father was born in 1911 when he was 46, and I was born in 1952 when my dad was 41. Both my father and grandfather were youngest sons. And a great-aunt on my mother’s side told me about her father riding through the fields when he was 13 shouting to everyone that Lincoln had been shot. It makes history seem very immediate and personal. I’ve been interested in history since I was young, probably because I’d heard these stories.

  10. It is very interesting. I have noticed the same in my own family. There is 11 years between me and my oldest sister. She and my brother had children before I graduated college. I didn’t marry till I was 30, not having children till I was 35. (My mother was then 74). By that time she already had 2 GREAT grandchildren – BEFORE my son was born.

  11. I liked the study. Saw lots of potential. Have been referring to it several places by using the graphic.


    For my studies, I see New England and later as a good source for research still pending (even with missing data). Lots of this type of work awaited modern computational prowess. Your blog and site represent the progress which has been more than sufficient. Data science is all that is necessary to show what we can do. What we don’t know is how to properly constrain enthusiasm about numbers that might lead to perdition.

    I will be posting on more studies that might be of interest to your organization .

    John M. Switlik
    Thomas Gardner Society, Inc.

    1. I ought to have given a link directly to the post. Some questions get lots of answers.

      As mentioned, I have pointed to the NEHGS a whole lot. Quora has some interesting questions to answer. Here are some examples. All reference Mayflower, though there is a general theme, to me (New England as the source for talking the American experience).

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