Researchers from the Vera Institute of Justice, with support from Google.org Fellows, collected data on the number of people in local jails at midyear in both 2018 and 2019 to provide timely information on how incarceration is changing in the United States. This report fills a gap until the Bureau of Justice Statistics releases its report on jail population statistics in 2019—likely in early 2021. Vera researchers estimated the national jail population and jail incarceration rate using a sample of 861 jail jurisdictions. The results are broken down by jurisdiction type and across years, showing diverging trends between urban, suburban, small/midsized metropolitan, and rural areas.