The 2025 Qualified Census Tracts (QCTs) and Difficult Development Areas (DDAs) are effective January 1, 2025. The 2025 QCT designations use tract boundaries from the 2020 Decennial census. The 2025 metro DDAs use ZIP Code Tabulation Area (ZCTA) boundaries from the 2020 Decennial census. The designation methodology is explained in the Federal Register notice published September 9, 2024.

The 2024 Qualified Census Tracts (QCTs) and Difficult Development Areas (DDAs) are effective January 1, 2024. The 2024 QCT designations use tract boundaries from the 2020 Decennial census. The 2024 metro DDAs use ZIP Code Tabulation Area (ZCTA) boundaries from the 2010 Decennial census. The designation methodology is explained in the Federal Register notice published September 21, 2023.