This study examines transit inequity in Metro Atlanta by measuring the spatial mismatch between transit supply and the needs of disadvantaged populations across five counties. Transit supply index is measured by using GTFS-based transit model to calculate 60-minute job accessibility, while a composite need index aggregates six disadvantage metrics from ACS 5-year data. The results reveal a clear core-periphery pattern: MARTA rail corridors in central Fulton and western DeKalb are oversupplied, while Clayton County, southern DeKalb, and southern Fulton are strongly underserved. A case study identifies two structurally distinct patterns of transit inequity: a county-wide infrastructure vacuum in Clayton produced by historical institutional exclusion, and an intra-county racial disparity in DeKalb produced by racial residential segregation and racially skewed transit investment. Both patterns reflect the lasting consequences of racialized governance, demonstrating that institutional inclusion in MARTA has not translated into substantive accessibility for predominantly Black communities.