Site neutral payment proposals are currently a key topic among policymakers. This +Insight explores how Medicare fee-for-service (FFS) site-of-service patterns vary across states and metropolitan statistical areas (MSAs). Our previous +Insights from February 2024 and March 2024 examined how site-of-service patterns vary across individual procedures that map to the same ambulatory payment classification (APC), and how they vary across rural and urban markets. We also analyzed services that are likely to be targets in site neutral payment proposals in our June 2023 +Insight.