I've owned my first home for a few years now, but have never truly known where my main water shutoff valve was, mainly because I've never really known how to identify it. I've looked around my utility room where my furnace, hot water heater, etc are, but nothing matches what I recall from my parent's home when they shut off the water there. For reference, my home was built in 1985.
The area I've circled in red is what I believe to be the main shutoff valve, but wanted to confirm before I messed with anything (note: I do not have any need to do anything with this at this time, just something I'd like to know in the event of an emergency). There are many valves in my utility room with my washer, dryer, furnace, hot water heater, etc. But based off of the images I've found from Googling, this seems to match some of the examples I've seen.
Slight side note, I'm also slightly confused at what looks to be a ground wire going from the green circle in the above image to the blue circle in the above image. This seems unnecessary and / or abnormal, but I'm not too familiar with how any of this would be set up "properly". Here are some close ups: