THE 1830-1850 CENSUSES
There are a few things you need to keep in mind about censuses this old. First of all, the United States in 1850 consisted of only 31 states, four territories, and the District of Columbia. Since this was before the Civil War, West Virginia had not been split off from Virginia, so those two modern states were just one huge state back then. What is more, most states were not finished forming counties so a lot of modern counties had not yet been split off from much larger ones back in 1850. In fact, only five of the six New England states, since Maine was still forming counties, and Delaware had the same counties that they have now.
The second thing to keep in mind was that these censuses were essentially done by hand since this was before adding machines, let alone computers. Hence there are a lot of mistakes in the data. What is available from the census bureau for 1850 is in pretty bad shape and is often very difficult to read. Indeed, what is shown on their website has pages that are virtually indecipherable. Fortunately, since the census bureau is just about the best run and most helpful federal governmental agency, with their cooperation, I was able to reconstruct the data since they mailed me clearer copies of those pages. Thus the county figures, with some minor corrections made by adding columns of males and females from the white people, free colored people, and slaves columns did provide correct aggregate totals when the total figure for the county was wrong and those totals did not add up to the given state totals. That is the other thing about these censuses that is shocking to the modern individual. The census figures provide break outs of whites, free colored people, and slaves. Remember this is before the Civil War and slavery was still a fact of life in 1850.
The last thing to understand is that the census counting was done by the federal marshals and assistant federal marshals back then. Some were more conscientious than others within a state, let alone between states. There apparently was little in the way of uniform standards for these censuses. Thus, in many states, there is little data available below the county level. Except for the six states mentioned above, the 2000 population figures given for the counties will not add to the total for the state given in 2000 because there are counties that did not exist in 1850 that have the missing population. In addition, just because a county has the same name now as it did in 1850, that does not mean that it has the same boundaries as it did back then. It is quite possible that the modern version is quite a bit smaller because new counties were formed and split off from the county in the intervening years. Thus the population figures given for 2000 might not be for the same geographic area as it was in 1850 even though the name is the same. In a few cases, the county shown in 1850 no longer exists under the original name and hence shows no population for 2000. In some cases, only the name has changed so the 2000 population is for the same geographical area, but the name is the one used in 1850.
A final word of caution concerns the four territories of Minnesota, New Mexico, Oregon and Utah. The area covered by the territory may not be identical to the one covered by the state of the same name in modern times. For example, part of the modern state of Washington was in the Oregon Territory. You will find a couple of county names listed under Oregon in the tables that are not counties in modern Oregon, but they are counties in modern Washington. Part of modern North Dakota was in the territory of Minnesota under the name of Pembroke County, the name of a much smaller county in modern day North Dakota. The counties in western New Mexico extended across all of modern Arizona. You need to keep all of this in mind in making comparisons between 1850 and today since you may be comparing apples and oranges. Three counties in the 1830 census for Michigan, namely Brown, Crawford and Iowa were later given to Wisconsin. Hence after 1830, those names and population figures are listed under Wisconsin. Also in 1830, Miller County in Arkansas included a part of Texas due to confusion about where the boundary was located. After 1830, that part of the population of Miller County shows up in various counties in Texas.
In the table showing the population totals for each state, it was necessary to make some adjustments. In 1840, the census bureau decided not to distribute the members serving aboard naval vessels back to their home states and counties. Instead they were simply added as a separate item to the bottom of the table. In the 1830 census, the state figures do not add up to the nationwide total shown in all the tables. It is one person short and I was unable to determine in which state the error occurred or whether the total for the country was simply overstated by one person. In a similar vein, I had to make adjustments to the state totals in 1830 census when the county totals did not add up and I could not find in which county the error occurred or whether the state total was simply incorrect. The total for the State of New York is 6,000 people shy of what the counties figures total. Similarly, Vermont is 7 people short in 1830. In cases where the county figures are not the same as shown in the tables from the census bureau, these reflect corrections made to cause the figures to add to the total for the state. In those cases, other data supplied made it clear what the figure should have been.