How we find the hills
Stillwater, Oklahoma is not a hilly town. Its hills are small and its streets were laid out on farmland. It still has 252 rideable descents, and we found all of them without leaving the desk.
The data was already there
Aircraft have been flying over the United States for years firing lasers at the ground to measure its shape, and the results are free to anyone. So is OpenStreetMap, the volunteer-made map of every road in the world. So is the aerial photography.
Nobody had put them together and asked the one question a skater cares about: where does the road go downhill, and how fast would I get?
Borrowing from cyclists
Working out where a hill starts and stops is harder than it sounds. Do it naively and every dip at a driveway splits one good hill into six useless fragments.
Competitive cycling solved this twenty years ago, just pointing uphill. Their rule is that a climb does not end the moment the road briefly flattens; it ends when the road has given back a real share of what you climbed. Flip that upside down and it finds descents beautifully.
That one borrowed rule is the difference between 252 hills and about fifteen hundred fragments, none longer than a driveway.
Ranking by what it feels like
Most route tools score hills with an invented points formula. We wanted the ranking to mean something, so instead we simulate a rider going down: gravity pulling, the wheels and the wind pushing back, starting from a single push. The number you see is the speed they would reach.
That matters because almost no residential street is long enough to reach top speed. A short steep pitch and a long gentle roll can look identical on paper and feel nothing alike. Simulating the ride sorts that out on its own.
What the map cannot see
It knows the shape of the ground. That is all. It has no idea about traffic, gravel, potholes, blind corners, parked cars, or whether skating a street is legal where you live. The top hill in a town can be a genuinely stupid place to ride.
The most useful thing we added was not speed at all. It was what happens at the bottom. A hill that runs out uphill slows you down for free. One that keeps dropping hands your speed to whatever comes next. In Stillwater, 159 of the 252 finish uphill, which is a big part of why the town rides better than it looks.
Go and look at it
The map is a shortlist, not a recommendation. Every hill on it deserves a visit in daylight before it deserves a run.