Can one web map reference separate web maps in ArcGIS Online Map Viewer?

No, a single web map cannot reference multiple, separate web maps because each web map is a unique configuration with its layers, symbology, extent, and settings. Web maps are designed to offer a unique map experience, so the add web map option is unavailable by design in ArcGIS Online Map Viewer. To combine elements from different web maps, recreate the layers and configurations in a new, single web map, which effectively merges the content from the other web maps rather than reference them.

Below are some alternatives to display content from separate web maps.

• Create a group or share the web map containing the data from the other web maps to allow access without referencing the maps. Refer to ArcGIS Online: Best practices for sharing for more information on sharing items.
• Use hyperlinks in pop-ups to reference multiple web maps. Hyperlinks are effective in directing users to other web maps for further information. Refer to ArcGIS Online: Configure pop-ups (Map Viewer) for instructions.
• Use ArcGIS Dashboards to create a dashboard incorporating the web maps. This allows users to view and interact with each map in a single, integrated interface.
• Use ArcGIS Experience Builder to create custom web apps where each map has its frame within the layout. This provides an organized presentation of multiple maps with separate widgets and interactions.