What are addresses and why they are so important to OpenStreetMap? This presentation will cover a wide variety of topics related to house number addresses as seen in the United States (with quick trips to Canada and Puerto Rico). How is an address mapped in OpenStreetMap (field work versus imports)? We’ll consider best practices, tools for both capture and validation of addresses, with a special emphasis on Quality Assurance. QA includes how I get data out of OpenStreetMap and run custom tools. We’ll conclude with a case study of Maryland’s addresses, including what has been done and current efforts.