With many regions in OECD countries facing declining working age populations, the geographical dimension of migration has become crucial for regional development. Where migrants settle within countries and how much they contribute to the local economies are important questions for policy makers. This report aims to address these questions using two novel datasets that offer internationally comparable information on migration and migrants' labour market integration across cities, towns and rural areas in OECD countries. The report also analyses different dimensions of regional development and provides new evidence on how migrants contribute to regional income, innovation, international trade and labour markets.