Difficult Development Areas 2026

Difficult Development Areas (DDA) for the Low Income Housing Tax Credit program are designated by U.S. Department of Housing and Urban Development (HUD) and defined in statute as areas with high construction, land, and utility costs relative to its Area Median Gross Income (AMGI). DDAs in metropolitan areas are designated along Census ZIP Code Tabulation Area (ZCTA) boundaries. DDAs in non-metropolitan areas are designated along county boundaries. DDAs may not contain more than 20% of the aggregate population of metropolitan and non-metropolitan areas, which are designated separately. To learn more about Difficult Development Areas (DDA) visit: https://www.huduser.gov/portal/datasets/qct.html, for questions about the spatial attribution of this dataset, please reach out to us at [e-mail]. Data Dictionary: DD_Difficult Development Areas Date of Coverage: 2026 Last Updated: 09-2025

低收入住房税收优惠计划（Low Income Housing Tax Credit program）下的困难开发区（Difficult Development Areas, DDA）由美国住房与城市发展部（U.S. Department of Housing and Urban Development, HUD）划定，其法定定义为相对于区域中位总收入（Area Median Gross Income, AMGI）而言，建筑、土地及公用事业成本偏高的区域。大都市地区的困难开发区以人口普查邮编表区域（Census ZIP Code Tabulation Area, ZCTA）边界作为划定依据，非大都市地区的困难开发区则以县界作为划定标准。单个困难开发区的总人口不得超过各自单独划定的大都市及非大都市区域总人数的20%。如需了解更多困难开发区相关详情，请访问：https://www.huduser.gov/portal/datasets/qct.html；若对本数据集的空间属性存在疑问，请发送邮件至[e-mail]与我们接洽。数据字典：DD_困难开发区 数据覆盖日期：2026年 最后更新时间：2025年9月。