How do I locate a specific County (St. Louis County) with the variable (COUNTY) or (COUNTYFIPS)?

I am trying to get an estimate of the number of black males in St. Louis City and also the number of males in St. Louis County. The City variable allows me to choose St. Louis City. However, the County variable does not have the names of the county. So, how do i go about identifying St. Louis County?

COUNTY codes (which combine the STATEFIP code and county FIPS code) are linked here. Which link you choose will depend on your sample(s) of interest. For example, if you are looking at samples from August 2005 onward, you will see here that the COUNTY code for St Louis is 29189, which is a combination of STATEFIP == 29 (Missouri) and county FIPS == 189.