Please read the Tableau Forum Guidelines http://community.tableau.com/docs/DOC-1251 before you post, I've had to make some guesses about what you were referring to and if you'd posted some sample data and a mock-up of your results it would have been easier for me to generate something.
Based on my understanding, there are a couple of options. The simplest is to use a Top N filter on the dimension of interest using the desired measure. Alternatively, you can use the INDEX() table calculation to generate a rank, then filter for that. I set up both in the attached, using Row ID (since there is one State/City combination per row) as the dimension of interest, and SUM(Sales) as the measure.
top N on map.twbx.zip 1.2 MB