# Gravity Hill: How does it work? **URL:** \ **Category:** Factual Questions\ **Created:** [February 19, 2003, 8:28pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200 "2003-02-19T20:28:52Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![beagledave](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@beagledave](https://boards.straightdope.com/u/beagledave)\ **Post date:** [February 19, 2003, 8:28pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/1 "2003-02-19T20:28:52Z")
Near Shullsburg, Wisconsin is a stretch of County U road referred to as [Gravity Hill](http://wicip.uwplatt.edu/lafayette/ci/shullsburg/gravity.html). I’ve never been there myself, but it’s close enough to my area that you hear about it occasionally. Essentially, if you drive your car to this section of the road, slip it into neutral…the car will move uphill while in neutral…“or so it seems” The locals claim it is unique…there may be other [similar](http://page.infinit.net/odipierr/autreslieux.htm) spots as well. Has anyone been to this place…or another similar spot? Anyone have an explanation behind the appearance of unassisted uphill movement? ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [February 19, 2003, 8:30pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/2 "2003-02-19T20:30:27Z")
It’s an optical illusion. The horizon isn’t flat, but your mind takes the horizon as being perpendicular to gravity. You’re going downhill. ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [February 19, 2003, 8:34pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/3 "2003-02-19T20:34:43Z")
You own link answers your question. ---
**Author:** ![jack\_ss](https://avatars.discourse-cdn.com/v4/letter/j/c77e96/32.png) [@jack\_ss](https://boards.straightdope.com/u/jack_ss)\ **Post date:** [February 19, 2003, 8:54pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/4 "2003-02-19T20:54:53Z")
There’s a Gravity Hill in Salt Lake City. I have been there once in the late 80s, and don’t remember exactly where it is, but it’s up the road from Memory grove, around City Creek. ---
**Author:** ![cmkeller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmkeller/32/118_2.png) [@cmkeller](https://boards.straightdope.com/u/cmkeller)\ **Post date:** [February 19, 2003, 10:13pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/5 "2003-02-19T22:13:01Z")
> [@](#): > > Has anyone been to this place…or another similar spot? > > Anyone have an explanation behind the appearance of unassisted uphill movement? I’ve been to Magnetic Hill in Moncton, New Brunswick, Canada, as well as the Confusion Hill Gravity House in Piercy, California (which is missing from the list in your link). It’s all an optical illusion. The mountain slope you’re on is so steep that the road you’re on, which is on a relatively lesser slope _but is still uphill_, appears to be downhill. So it seems to you that your car (or the rolling ball, or whatever) is traveling against gravity…but it isn’t. ---
**Author:** ![Bongmaster](https://avatars.discourse-cdn.com/v4/letter/b/6a8cbe/32.png) [@Bongmaster](https://boards.straightdope.com/u/Bongmaster)\ **Post date:** [February 20, 2003, 9:36pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/6 "2003-02-20T21:36:10Z")
There is a similar hill in Bucks County PA, about 1/2 an hour from my home. It all has to do with the lay of the land, it makes it appear to be a hill going up but in reality you are going down. ---
**Author:** ![Baron](https://avatars.discourse-cdn.com/v4/letter/b/9de0a6/32.png) [@Baron](https://boards.straightdope.com/u/Baron)\ **Post date:** [February 20, 2003, 9:50pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/7 "2003-02-20T21:50:32Z")
And I thought our Gravity Hill in northern NJ was the only one…(off Rt. 208 in Wyckoff) ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 20, 2003, 10:04pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/8 "2003-02-20T22:04:43Z")
Near Shullsberg ? The excess gravitational attraction may be due to the consumption of large quantities of tasty 5 year old cheddar from the local [cheesery](http://www.explorewisconsin.com/shullsburgcheesestore/). 😉 ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [February 20, 2003, 10:20pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/9 "2003-02-20T22:20:05Z")
One common form of the illusion is that you have a very gentle slope, with some reference like trees or telephone poles that happen to lean a little bit more than the slope, in the same direction. The slope isn’t steep enough to be visually apparent, and you tend to orient on the tree or telephone pole as vertical, leading you to think the slope is in the opposite direction from what it actually is because you are judging it by the angle it makes with the pole. Consequently, objects can roll “upill”. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [February 20, 2003, 10:43pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/10 "2003-02-20T22:43:16Z")
I remember seeing a ‘gravity hill’ about 20+ years ago on one of those god awful 80s shows, **That’s Incredible** I think. ---
**Author:** ![mipiace](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mipiace](https://boards.straightdope.com/u/mipiace)\ **Post date:** [February 20, 2003, 11:24pm UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/11 "2003-02-20T23:24:17Z")
There must be “Gravity Hills” all over the place. The one in lake Wales Florida is called Spook hill and supposedly when you park at the “bottom” of the hill you are on an Indian burial ground. The ghosts pull you back up the hill to move you from their sacred spot…it’s the same principal though, it’s actually down hill. ---
**Author:** ![Strainger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/strainger/32/244_2.png) [@Strainger](https://boards.straightdope.com/u/Strainger)\ **Post date:** [February 21, 2003, 12:07am UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/12 "2003-02-21T00:07:26Z")
I can’t believe that Booger Mountain in Cumming, GA wasn’t mentioned in **beagledave’s** link. :mad: ---
**Author:** ![notquitekarpov](https://avatars.discourse-cdn.com/v4/letter/n/71c47a/32.png) [@notquitekarpov](https://boards.straightdope.com/u/notquitekarpov)\ **Post date:** [February 21, 2003, 12:37am UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/13 "2003-02-21T00:37:21Z")
BTW there are also numerous rivers and creeks that appear to flow uphill due to the same optical illusion… ---
**Author:** ![japatlgt](https://avatars.discourse-cdn.com/v4/letter/j/df705f/32.png) [@japatlgt](https://boards.straightdope.com/u/japatlgt)\ **Post date:** [February 21, 2003, 2:23am UTC](https://boards.straightdope.com/t/gravity-hill-how-does-it-work/156200/14 "2003-02-21T02:23:33Z")
Yeah, there’s one in Nashville. Same deal. It’s an illusion.