To obtain county-level data, we recommend you first consider what’s available through the IPUMS NHGIS site. Unlike IPUMS USA, which provides census microdata, NHGIS provides census summary tables.
For recent censuses (post-1940), the geographic information available in census microdata is limited in order to preserve the anonymity of respondents, so many counties are unidentifiable. (Generally, in ACS samples, IPUMS USA can identify only counties with populations over 100,000, and not even all of those.)
In contrast, the 5-year ACS summary tables that are available via NHGIS can identify all U.S. counties. The catch is that there is a limited number of cross-tabulations available, so you might not be able to measure exactly the characteristics of interest.
To find what’s available for your subject of interest, go to the NHGIS Data Finder and select the following data filters:
There are 20 tables that fulfill these conditions, including several that are broken down by age, and one that breaks down veteran status by educational attainment.
Note that the “Military Service” topic filter does not cover all ACS tables that include the “In armed forces” labor force status. That topic is more focused on veteran status tables. To find all tables that cover the “In armed forces” status, use the “Labor Force and Employment Status” topic filter.
If you find that you’d still like to use IPUMS USA microdata (possibly to measure some characteristics that are not available in the summary tables), the general method of producing summary statistics would be weight each observation using the person weights. The exact steps for doing that depends on the software package you are using, but this forum answer provides general guidelines.