This is the only Arkansas location I know of where your car can roll up a hill. It seems to defy logic and gravity, but it's actually an optical illusion. There are several hills like this, and the one thing they all have in common is an obscured horizon. When the horizon is obscured, our brains can't readily process our position. At Gravity Hill in Helena, the trees are angled oddly too, which contributes to the illusion. More about the effect
The truth behind the effect is boring, but when I was doing the research for this blog post, I found out much more interesting legends about why you roll uphill. Apparently, the hill is haunted. Who is it haunted by? Who knows. Some claim it's a team of high school football players who died in a bus crash on the hill, others that it is little children who died in a bus crash, and I even read one retelling where it was a grandma who died on the road. The legend of the little kids is my favorite. Those who tell this story add a great, spooky detail: if you sprinkle baby powder or flour on your bumper, you'll see the tiny hand prints where the kids pushed your car up the hill. That kind of detail just makes any urban legend better.
I had never heard of the baby powder legend until last week, so I've never tried it. I've always heard it was a fun, optical illusion. Don't let me spoil your fun, though. Sprinkle some baby powder on your bumper and have at it! Next time I go to Helena, I may try it myself.
Gravity Hill is actually Sulphur Spring Road. From AR 185, turn north onto Sulphur Spring and keep going until you get to the stop sign at the intersection with US 49. The stop sign is the "bottom" of the hill. If you put your car in neutral, you really do roll "uphill" for about 200 feet. You can do it again and again if you want. Feasibly, you could also roll anything else you wanted to roll uphill...if you're weird. If you look at the Google Street View (this view is looking "up" the street, from the stop sign at the "bottom" of the hill), you can kind of see the unusual angle of the trees.
The cops won't ticket you for breaking the law of gravity, but it's a real street and they will ticket you for breaking traffic laws. I'm sure rolling backward on a public street counts as breaking the law. Don't blame me if you get a ticket for acting silly. It's not a very busy street though, so use your best judgment.
If you're into hauntings or history, you should visit the Helena Confederate Cemetery too. Many say it is haunted by some of the soldiers who lost their lives in the Battle of Helena on July 4, 1863. The "the Stonewall Jackson of the West" is buried there. It's located on Holly St in Helena.
I'm surprised there is no legend that it is Confederate soldiers pushing your car uphill. I'm up for starting one.