Maps appear all over the web but the core structural language of the web—HTML—does not natively support them. Adding dynamic or interactive maps to a web page or web application can involve complex JavaScript code that is difficult to reuse between contexts.Web developers are starting to have opportunities to change this. Some newer web development frameworks are designed to support HTML page elements with custom attributes as a way of defining behaviors. These frameworks anticipate web components, an emerging standard for creating fully custom HTML tags. Custom attributes and elements make it possible to effectively expand HTML to include `{my-map}...{/my-map}`.This talk will demonstrate how to use existing JavaScript map libraries to create flexible, reusable maps that take the form of HTML elements with custom attributes. Looking forward, we'll explore how web components let us take this technique even further and create true custom HTML elements for maps and the display of other geo data.Crafting custom HTML map elements doesn't just mean making maps a first-class citizen of web page markup, it offers a whole new way to create and share web-based mapping tools between applications and organizations.