I've been there. Loved it! Plan on going again. Thanks!

I was waiting until I got the basic answers out of the way to suggest orchard grass. When I was a kid in SoCal we had orange groves all around us. One grower sprayed diesel fuel to keep the weeds down. Another one encouraged nutgrass to grow up by watering too frequently. The one with the nutgrass had the side benefit of discouraging us kids from running through, picking the oranges, and throwing them at each other. We gravitated to the one that smelled like diesel fuel because we could run faster on the hard surface. There is an orchard owner in my area (somewhere) who piles mulch between the trees. I have seen the pictures, but don't know much more than that. There were several feet of mulch. He claims that he never has to irrigate because the mulch holds all the moisture down.

Almost impossible to tell from just a photo. Location can help to narrow things down but many cool season lawns (those located in more northerly locations) are blends of various turf grasses. If you can take a good sample, including roots, into your local extension service office, they should be able to come pretty close if not nail it.

In Texas the state plants something called King Ranch bluestem or KR bluestem. Well, maybe they don't plant it, but it is literally everywhere. When I moved to Bandera, Texas in 2014 I didn't see any. Now it is everywhere. The fringe of my lawn still has some, but the St Augustine seems to stamp it out (like almost all other grasses). I would not be at all surprised that KR bluestem has reached the Raleigh area (is that one of the Carolinas??). It looks fine for maybe 2 weeks after mowing, but once it send up a seed head, it jumps to about 18 inches tall overnight. I've never walked on it barefoot, but I suspect the clipped off seed stems are hard on the foot. It does not get very dense, either.