It had a 32-bit address bus, so that was a nice, flat 2GB of directly addressable locations.
Edit: You might've been asking a different question. Toward the end, lots of Amigas had MMUs, either as a separate chip or built in to the CPU. VMM and similar programs used the MMU to implement paging.
Those are both interesting answers, and I didn't really know anything about the Amiga's architecture (other than to have imagined wrongly that it might have had 16-bit addresses). Thanks.
Edit: You might've been asking a different question. Toward the end, lots of Amigas had MMUs, either as a separate chip or built in to the CPU. VMM and similar programs used the MMU to implement paging.