In days of Analog TV in America I was able to pickup Philidelphia Stations after rain storms in Southern Brooklyn (By water, not sure how big of a factor), which would be roughly 100 miles.
Wow, was the signal clear?
Anywhere really? The AM band is just above long wave and during the right conditions can travel thousands of miles. Personally I've talked to people in South Africa broadcasting under 50 watts just above the AM band. A friend of mine has contacted almost every country in the world with 5 watts of power and a wire antenna. Radio is magic.
Oh to add to this Ive easily picked up New York City Area AM stations close to the Canadian Border (~300 miles) with a regular walkman radio especially at night (I believe there are power restrictions during the day)
That's really cool. At night certain AM stations are required to turn their transmitting power down due to the way signals travel in the evening. We have an AM station near us that uses the mountain and multiple antennas to get their signal out during the night with low power; I'll try to find a picture of it for you.
Broadcasting
A place for all those who surf the [air] waves. Someone has to punch the buttons, right?