How big of maps can source support?

[Raziaar]

I'm just curious... because in the game, we all know there are quite a few loading times. Does that signify tons and tons of new maps being loaded, and all pieced together, or are there multiple loads on one large map, and would it be possible to create a large map without all those loading times at the expense of performance?

 

[PvtRyan]

Maps can be pretty big, I believe 16384 units standard and double that if you're pushing it, a unit is one inch in this case.
But map size isn't the problem, keeping the map interesting is, you'll still have to obey the entity limits, so you better have small densely detailed map, than a huge boring plain one.