As Medi-Cal enrollment expanded during the early years of ACA expansion (2014 and 2015), county health department spending in California also swelled. For most counties and regions in the state, the two measures tracked closely. However, exceptions in Northern California (with high enrollment and low spending growth) and Central California (low enrollment but high spending growth) show that other factors may also have had an effect. Importantly, if Medi-Cal is turned into a capped block-grant program at the federal level, counties would be heavily impacted and could be left with budget shortages.