Creating a new map in Portal automatically adds content that I can't delete.

[WillPlatt]

When I create a new web map (Content>My Content>Create>Map) Portal automatically adds a feature layer and a topographic layer from my data.  I cannot delete either of the layers.  Is there a default map template or something that I can edit or delete to have this behavior stop?

ArcGIS Server 10.6.1

[JohannesLindner]

That sounds like the base map, which is chosen by your portal's administrator.

If your admin made multiple base maps, you can switch between them:

You can also switch it off: