Root beer is actually steeped in history from pre colonial times here in America.
Originally made from from the roots of the sassafras roots and depending on the region with other herbs.
"Root beer is a sweet North American beverage traditionally made using the root bark of the sassafras tree Sassafras albidum or the vine of Smilax ornata as the primary flavor. Root beer is typically but not exclusively non-alcoholic, caffeine-free, sweet, and carbonated."
I found this link full of information on the history of root beer.

Of course there are many brands to choose from now. I grew up on A&W root beer-and I still prefer this brand but their sugar free and caffeine free root beer. (many now have caffeine added)
Root beer floats
Where did root beer floats come from??
( I make mine with vanilla ice cream and root beer-add a straw and a spoon. some add other flavorings or whipped cream on top, some add alcohol.)
"Also known as the “Black Cow,” the root beer float got its start in Colorado in a mining camp. Frank J. Wisner of Cripple Creek, Colorado, gets the credit for inventing the “Black Cow” way back in August of 1893.Aug 6, 2019"

Linda mentioned root beer popsicles-I have never had one but found a photo