The conference, "Measuring Migration: How? When? Why?", was an interdisciplinary and international venue for academics, practitioners, and students to explore the idea of "measuring" migration" using a variety of methods from interdisciplinary perspectives. Participants explored the ethics and implications of what it means to track migratory flows and discussed when this might be appropriate and why these data are helpful/harmful. This conference was hosted in hybrid format online and in-person at the University of Oxford on June 9-10, 2022 (Oxford, England, UK) and was sponsored by MigrationOxford (previously known as the Migration and Mobility Network) and Nuffield College. There were over 300 participants registered from around the world, spanning six continents and dozens of institutions. There were over 30 paper presentations on 10 panels and four keynote addresses/panels that took place over the two days. The proceedings included in this volume cover the majority of the papers presented. We would like to thank our colleagues who served on the program and steering committees, as well as those who helped us on the ground as local coordinators. We are particularly grateful for our funders at Nuffield College and MigrationOxford for their faith in the success of this event. Most of all, we would like to thank our speakers and presenters who came in-person and online to participate in the first Measuring Migration conference in this series.