The US Census Bureau, in association with the Federal-State Cooperative Program for Population Estimates (FSCPE), has recently released updated population estimates on the national, state, and county level. Updated national estimates are available on a monthly basis, and annual estimates are available for 1990- February 1997 by age group, sex and race. On the state level, estimates have recently been updated through 1996 for demographic components, age groups, and sex, increasing the time series covered to 1990-1996. On the county level, 1990 and 1996 estimates are now available for population, population under and over 65, and demographic components of change. All files are available as ASCII text, with some of the larger ones compressed in .zip format. Documentation and layout of files is available.