About the Texas Slavery Project Database

The Texas Slavery Project database contains population counts for each Texas county with surviving tax returns from the Republic of Texas era. During the years 1837 to 1845, residents of the Republic of Texas attempted to finance their new nation with taxes collected on a wide range of personal property held by local citizens. One of these categories of taxable property were the enslaved men and women held by planters in Texas, and listed in the surviving tax records. The Project used these original records to count the number of slaves assessed in each county for the 1837-1845 period, as well as the slaveholders who held this property, to collect the numbers that make up the Project's online database. This database contains counts for:

Original Sources for the Database:

Microfilm A: Negative microfilming done by the Texas State Library and Archives, available on site (in their genealogy section) and by purchasing copies of the microfilm reels.

Microfilm B: Positive microfilming done by the Texas State Library and Archives, available on site and through interlibrary loan.

TSLA: These numbers were arrived at by consulting the original documents in the Archives division of the Texas State Library and Archives.

Most of the numbers in the database come from the negative microfilming available at the Texas State Library and Archives (TSLA). Information that was either missing or illegible in this microfilm series was obtained when possible from the positive microfilm version or the original records on file at the TSLA. Remaining gaps in the database that reflected an absence of historical records rather than an absence of slave and slaveholding populations were filled in using statistical estimates.

Statistical Estimates of Missing Data:

Because the records of tax returns from some counties have not survived, estimates for some county returns were generated using established statistical techniques and are made available here in the maps and database. These were generated only for counties where slaves and slaveholders were known to have lived at a particular time, but the records have simply not survived.

This would be the case in a place like Robertson County, which has surviving information on the number of slaves and slaveholders in the area for the years 1837-1840 and 1842-1845. The returns for 1841 are missing, although there were certainly slaves and slaveholders in the region during that year, so a statistical estimate for 1841 has been created based on the returns collected from the original records for the other years.

Using visualization techniques, we grouped counties with similar population patterns and trends, using the arc of population shifts in particular counties to estimate changes on other similar counties whose data was missing. The population trends in other counties seemed to have followed trends that differed from most counties, and in those cases we used the average of the preceding and exceeding years to estimate the missing data.

In both the Project's maps and database search engine, users can choose whether or not to include the estimated numbers in the database.

For a detailed explanation of the techniques used to develop these estimations, please download the Texas Slavery Project Database Estimation (PDF) paper.