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1880 and 1900 Idaho Census Data: Home

About the Project

About 1975, students at Idaho State University began putting the information contained in the Idaho Territorial Census for 1880 into machine-readable format in order to conduct historical research on Idaho's historical population in an electronic format. In 1989, awards from the State Board of Education/Higher Education Research Council and the History Committee of the Idaho Centennial Commission facilitated completion of the coding of the 1880 census and began the task of coding the 1900 census. Also at this time, the project expanded to involve students not only at ISU but also at the University of Idaho, Boise State University and Albertson College (then, the College of Idaho).

The data used in this study relating to Idaho's population in 1880 and 1900 were supplied in partially-proofed form by the Idaho State University History Department (under copyright agreement with the Idaho State Board of Education).

A Guide to Reading Census Data

A Guide to Reading Census Data

Melissa Leaman

Department of History

Idaho State University



Census data is incredibly useful for learning details about the people of the past. Not only for statistical and scholarly purposes, but also for those doing research on family. Anyone who has begun the journey of researching their ancestry has met (or will meet) a stalling point. Census data can push the journey forward, whether by providing direct records of family or records of the people they interacted with. But to get this information, we need to understand how to use the data in front of us.

Let’s start with an overview by opening the file marked “Ada1900Analysis” in the “1900 Census” folder. There are both Excel or Google Sheet formats available. Some of these charts may not seem helpful at first. It’s just a big picture chart, right? But as we will see, even big pictures can guide our search and provide helpful clues. 

  • Sheet 1: A broad overview of population growth. We see a big jump during the 1850s and 1860s, which a quick Google search will tell us fits with the Idaho Gold Rush. This tells us that mining claim records might be useful in our ancestry research down the road, depending on what additional information we learn.
  • Sheet 2: The gender breakdown here shows us a decent balance between male and female. Idaho is a state at this point and as the state capital is in Ada County, more families are likely to settle in this area. In strong mining regions such as Owyhee County, we see greater discrepancies between male and female and a declination in population growth. 
  • Sheet 3-6: These charts give us some insight into where these people came from first. Sheet 3 shows where the census parties migrated from. Note that this does not indicate they all moved in 1900, but where they came from before in order to be in Idaho at the time of the census. This can be incredibly useful for ancestry research as it gives us the next steps in our search for records. Sheets 4 and 5 provide information on the parents of the census participants, with sheet six continuing the place of birth breakdown to show us states, provinces, and countries of birth. 

Column A contains the codes used in the census record, we’ll come back to this. Column B tells us how many people came from each area. This can provide us with some additional questions to consider: how many people came from that particular state? If there are a substantial number, did they travel together? A group traveling together might mean additional letters or personal journals in an archive somewhere. Your great great great grandmother might not have kept one, but what might her best friend say about her in her own diary?

  • Sheet 7 is our final chart, giving us an occupational breakdown. Again, column A is the code used in census records, column B reflects the number of people in this occupation. A perusal of this list tells us what jobs were in high demand and just how many potential occupations were available at this time.

  • Sheet 8 is the juicy one. It is here that we get the specific data that we need to create a full picture of an individual or family.

Let’s use the first person in the Ada County 1900 Census, Edward Lewis, as an example of all the information that can be gleaned from census records. You will also want to open the file marked “1900codebook” to use for reference. The number of columns listed in the codebook slightly differs from those in our chart. This is because the codebook refers to Idaho’s statewide census data, without the helpful county breakdown here. 

To the left side of the name, we have location information. Most of this is organizational information, the order in which families were visited, though this can give us ideas of who might be neighbors or decently close to the people we are interested in. Column B: Town tells us what area of the county the individual lived in. In this case, the Lewises live in the Boise Precinct. 

Now let’s dig into the right side of the names, where column titles provide extra direction for us. Relationship codes show that Edward is the head of the household. Below, Anne is assigned code 2, indicating she is Edward’s wife. Robert and Kent have code 5, identifying them as Edward & Anne’s children. Let’s highlight all four of these then, to create a family picture. The codebook tells us all four of the Lewises are white, that Anne is 8 years younger than Edward, they’ve been married for four years, have two children, and considering the oldest child is three, began having children very soon after marriage.

Columns RST sends us back to the codebook. We learn that Edward was born in Pennsylvania, but Anne and the two boys are Idahoans by birth. This tells us that Edward was likely single or a child when he moved to Idaho. While it is not impossible that he had a previous family, his age of 30 now (25/26 when he married Anne) tells us that is unlikely.

We also learn that Edward’s parents came from Western Canada by the code 192 in columns S & T. Anne’s father is from Kentucky and her mother is from Missouri. Each of these pieces of information tells us more. Anne’s parents immigrated to Idaho and stayed there long enough to have and presumably raise Anne. Edward’s parents went to Pennsylvania at some point and then Edward went out West. What might have driven these long and arduous journeys are questions we might ask? What opportunities were these parents seeking versus the children?

Column X tells us that Edward is a mechanic. This might direct us towards potential company records to learn more about the Lewis family. Finally, we learn that both Edward and Anne can read, write, and speak English, and they are renting their home at the time of the census. 

As we see, what looks like a bunch of confusing numbers can provide quite a bit of useful and interesting information. And it can point us to our next research steps. Who knows what else you might find?

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