Which do you call’em in your neck of the woods?
I, personally, call 'em fireflies, but I often hear both names. (FWIW, they are technically neither flies nor bugs, entomologically.)
Growing up we called them lightning bugs, but now I use both interchangeably.
You hear both of them around here. When I was small, lightning bug was more common.
Same here. I would have voted “both” if I could have.
Another who would have said both had it been available.
I grew up calling them fireflies in Louisiana. As best I can recall, that’s what everyone in my home town called them, though I think most people would have known what you meant by “lightning bug”.
But you can only get a “hug” from a lightning bug 
Side issue: how many have gathered a jar full of them to use as a flashlight?
Lightnin’ bugs. I used to cry when the boys would squish them on their pants leg to make glowy spots. That’s just mean.
Where’s the option for: I would prefer “firefly” but have not seen these creatures in my life so I have no strong preference.
I’ve never done that, but I used to be able to lure them to land on my hand with a penlight–I learned the timing of the flashes and copied it. Apparently, they aren’t too fussy about the color as long as the timing is right.
Both names are used about equally in Wisconsin. Talking to a kid I’m more likely to say Lightning bug.
I clicked “other” because I use both.
I clicked “other” because I’ve never heard either term used here. I don’t know whether we even have them.
I grew up outside Philadelphia and we called them lightning bugs. The first time I saw the word “firefly” was when I read it in a book.
We called them lightning bugs when growing up. We used to catch them in mayonnaise jars.
We always called them fireflies, but there were always people in the same location who called them lightning bugs.
“Lightning bugs” was the common term while I was growing up in Texas; I use both terms interchangeably now.