Whether Supplemental Nutrition Assistance Program (SNAP) benefits are adequate to provide food security for eligible households is an important and timely policy question. While the nominal value of SNAP benefits is fixed across states (except for Hawaii and Alaska), variation in food prices across geographic areas is dramatic, and the real value of SNAP benefits varies widely across the U.S. Our research provides new evidence on geographic variation in the adequacy of SNAP benefits to purchase the Thrifty Food Plan (TFP). Using multiple methods to estimate the cost of the Thrifty Food Plan (TFP) faced by households across the nation, and several measures of the SNAP benefits available to them, we consistently find that a substantial fraction of SNAP-recipient households receive benefits that are insufficient to purchase the TFP. Our primary estimates indicate that SNAP benefits (plus 30 percent of income) are insufficient for approximately 20-30 percent of households to purchase the TFP. Sufficiency rates increase monotonically as we expand the distance within which the household is assumed to be able to shop. For households who are unable to afford the TFP, average dollar shortfalls between the cost of the TFP and SNAP benefits (plus 30 percent of income) are often as large as $150 per month. When shoppers are assumed to be able to purchase the TFP at the minimum-cost store in the area, SNAP benefits are sufficient for over 90 percent of households. However, this assumption seems unlikely to hold for many SNAP households.