Underinvestment in primary care and erosion of the primary care physician workforce are resulting in patients across the US experiencing growing difficulty in obtaining access to primary care. Compounding this access problem, we find that the average patient panel size among US family physicians may have decreased by 25% over the past decade (2013 to 2022). Reversing the decline in access to primary care in the face of decreasing panel sizes requires both better supporting family physicians to manage larger panels, such as by expanding primary care teams, and substantially increasing the supply of family physicians.