Where can I find County level income data for college graduates? Does anyone know where I can find data regarding the median income of college graduates by county in the US? Can't seem to find it searching through the census website. 

The goal here is to obtain an opportunity cost basis to explore geographic wage differences in one field. I will be taking a ratio of field wage to this median income data. It would be more meaningful if I could find estimates of median income by educational attainment, rather than just general population data.
Try looking at the Current Population Survey. Using a tool like DataFerret you can find education (PEEDUCA) and income (HUFAMINC), along with the county code. That gives you the micro data, finding median income by education level can then be done in your statistics package of choice.