I drive Uber so I see them EVERYWHERE. So far:

Watched a whole family rolling down Blvd of the Allies through the intersection of Stanwix street at around midnight one night.

Had a few walk right across Grandview Ave in front of me on Mt. Washington.

Seen quite a few rolling through random side streets in Shadyside/Squirrel Hill/East Liberty.

I literally see at least two dozen deer per night. You just have to be watching for them.