Cleaned out the trunk of my car,before I get ready to drive it, came across this large plastic piece was in the front of the trunk. Am I correct in assuming, this is the splash shield, that mounts under the front of the car? Attached is a photo

Is the splash shield missing? That'* definitely a splash shield.

Thanks for the quick response!
I did not see one the last time I was underneath the front of the car

You'll want it. Not just for the obvious but without it the airflow through the front and under the car gets channeled differently. You will get less through the radiator and when really hot you can overheat.

Yeah, just confirmed on mine: That'* the front air baffle/splash shield the screws get knocked out (or fall out) on the back edge (which is to out left in your picture. When I looked at mine just now I found yet another one missing.

Some people just take them off, but I agree with carfixer007 above ^^^^^^^ that you want it. By the placement I think that without it you take a chance of having less air flowing over the top of the engine from ram air and/or the fans. It would get out the bottom pretty easily and leave a heat sink in the back half of the top of the engine bay.