Americans are a mobile people. Instead of making a life where we were raised, we often pick up and move far from our families, hoping to make our fortunes elsewhere. But because we left our hometowns with no shame or malice, when the holidays come around we all–as consistently as birds heading south–brave the crowds at various transportation hubs and slowly shuffle back home. A new map created from check-ins on Foursquare paints a picture of this holiday travel and how Americans get from one place to another in different parts of the country.

The map shows plane flights (in blue, based on two consecutive check-ins in different airports), train rides (in red, based on same-day check-ins in different train stations), and car trips (in white, based on check-ins on roads). Together, they form an outline of how America travels and even how America's population has spread across the country.

If only the plane trips could somehow indicate direction, this map would be more interesting. Even so, we can see which cities are connected to each other by traveling loved ones. Florida and the Northeast are tightly linked, with people flying south to see the grandparents or grandparents flying north to see the children. And the urban, coastal connection is also clear, with San Francisco, Los Angeles, and San Diego's lines mostly skipping the flyover zone to land in the Northeast. Apart from family dynamics, though, the lines are also a clear indication of our hub flying system. Dallas, Atlanta, and Chicago are all glowing blue beacons due to the many flights in and out of them.

The map also makes a compelling argument for high-speed rail. In places where rail travel is robust–especially in the Northeast Corridor and around Chicago–rail travel is a viable and much-used option. The rest of the country, with some exceptions on the West Coast, is free of the red indicating a train trip. The easy argument would be that places where cities are far away aren't right for train travel, but that's thinking small. Far-apart cities aren't right for train travel because the trains are too slow.

But cities are far apart, and more insular, away from the coasts. As your eye travels east to west, you can see the entire interstate highway system first outlined by check-ins and then slowly fading away to near nothingness. The cities out west are farther apart, yes, but they also lack blue and red lines emanating from them. People in these cities seem to travel less far for the holidays, perhaps because they've stayed put more than people on the coasts. Then again, they might just have better things to be doing than using Foursquare.

When is this travel happening and how can you avoid the crowds? To find the answer, check Foursquare's timeline. The peak for flying is in the lead-up to Thanksgiving, with another smaller peak near Christmas. The trick, not surprisingly, is to go early. Or, less pleasantly, travel the day of: The amount of travel drops quickly on the actual holidays.

George Monibot has written about a concept he calls "love miles," essentially the increase in carbon footprint we all have because, in a globalized world, we tend to have relationships that require a lot of travel. We live in a world where we can move wherever we want, and travel whenever we want (provided we can afford it). That's mostly a good thing. But it also raises the question of figuring out how to balance those advantages with the fact that each love mile we travel isn't so great for the planet. Below is a look at the whole graphic (click to zoom)–safe travels: