My roots are neither deep nor firmly planted. Like many in my generation, I didn’t grow up among a bevy of siblings or in a house that swarmed with cousins at Thanksgiving. My family was American-nuclear, consisting only of myself, my parents, my little brother and our menagerie of thematically named pets. We lived in a cookie-cutter suburb with a bigger-better-more mentality, a place on the nouveau-riche outskirts of Detroit, where, as a kid, I spent a lot of time daydreaming about the great big world out there. Big cities, blue yonders.

Many years and five cities later, my Seattle Thanksgivings tend to be teeming with friends, piled high with mismatched side dishes and stuffed with an enormous turkey. Cooks come and go from the kitchen all day long, and when it finally comes time to eat, a chain of tables and chairs are pushed together, chaos momentarily unfolds, and my nearest and dearest sit down to express—often in words—their entirely heartfelt gratitude.

This is Friends Thanksgiving, a delicious aspect of transplant culture that avoids taxing holiday travel and allows a girl to spend the day thankfully intoxicated—without drama, a twin bed or political attack from the other side of the Bush divide. By no means anti-family, Friends Thanksgiving welcomes kin of all kinds and repeatedly requires the culinary guidance of mothers nationwide.

Several years ago, The New York Times Magazine gave a name to clusters of transplants: urban tribes—contemporary sociological alternatives to geographically proximate blood relatives, city-dwelling packs of friends, a new sort of me and mine.

Indeed, today’s American cities are saturated with transplants, relocated and reinvented. Flung from all over hell and gone, we’ve uprooted ourselves for an independent planet cruise. Touched by wanderlust, we’ve become masters of digital communication—putting six degrees of separation to the test and trying to throw our arms around the world.

It might seem easy to pick up and move these days. Rent a truck, slap some tape on some boxes. Beef up your wireless plan. But the truth is it’s still not easy to be all alone, unattached and unconnected. So why do we hit the road?

To belong. Anything to feel like part of something. To be surrounded by unrelenting curiosity laced with possibilities. To be understood and to understand how it all comes together, combines. To chase the tide, trace the horizon. To feel the friction of differences.

And of options. It’s not that I don’t love my family. I’ll always be their little alien, foreign, familiar and profoundly tethered to them by childhood and DNA. But I didn’t choose them—not the way I’ve picked my tribe or the way my tribe picked me: for who I am, for what they see in me.

No doubt the notion of family in this country has changed significantly in just a couple generations’ time. It seems families started off the 20th-century living under the same roof before branching out to the block, the borough, the ’burbs. Pioneering transplants—immigrants, migrants, Californians—have been cutting the geographical umbilical cord and striking up unexpected unions for decades. When my parents flew the coop they did exactly that: They formed a bona-fide family with the neighbors.

Here’s how it began as it begins: Fueled by the cultural frenzy of far-away college education, considerable willpower and, um, dreams, I took off across state lines at 17. I had nary a clue, but I lusted nonetheless for mass transit and a skyline. And suddenly there I stood: alone on the doorstep of my freshman-year dorm, a classic deer in headlights, my parents and brother pulling out of sight in their 1990s minivan.

Nothing could have prepared me—or prepares anyone—to meet the motley crew of beautiful oddballs I came to know and love in college. Sure enough, between the usual heartbreaks and benders, our troupe of friends became a clan, a family strung together with common threads and determination. Of course, school has long been the place for making lifelong friends. (My mother still gets Christmas cards from hers.) But modern urban tribes have changed the way we hang together.

Today my college crew is once again scattered around the globe—saving rivers, making music videos, singing Abba songs on Broadway. Thanks to cell phones and proletariat air travel, we talk often and visit when we can. In the meantime, our patchwork family just keeps growing.

Forming a tribe is a bit like building a dream team. Anyone is eligible, and members can be selected at any time according to a delightfully broad range of criteria. Through a series of serendipities, time cobbles together old friends and mutual friends, former lovers and new loves, as well as blood-related brothers and sisters in cities all over the place. With every wedding, every project, every random drunken weekend in the woods, the dream team just expands. And more and more, the entire world becomes a home.

I landed in Seattle on a sort of wild ricochet. After my postcollege plans dissolved in Rome, I had hightailed it to Los Angeles where my high-school best friend promised to take care of me and my terrific blues. Then a stroke of insanely good luck in the employment department allowed me to discover very rapidly that Hollywood was not a fit for the bookish likes of me. If nothing else, I missed seasons too much.

The next thing I knew, I was in Phoenix for a wedding of two college friends (who also happened to be living in L.A. at the time). There, I ran into another college friend and accidentally ignited a classic wedding romance with a member of the bridal party. Both the friend and the inamorato had just moved to Seattle. On the heels of such resplendent coincidence, I booked a ticket to the Emerald City and fell in love with it instantly. A few months later I moved.

Thanks to tribal connections, I had about 10 would-be friends right from the start. Of course, you never know who’s going to stick. But a lot happened in the first few months after we joined forces, and, as it does with family, it bonded us to one another.

On Sept. 11, 2001, I woke up in a house I’d lived in for nine days and pulled myself out of bed because we were expecting an early morning visit from the cable guy. On my way to my toothbrush I encountered one of my roommates. She looked totally confused and said something about the television. Time passed and the sky emptied of planes. Seattle turned strangely quiet. We spent the rest of the day with our 10 friends, and I suppose it was clear even then: We were family.

Four years have passed, and our supertribe—in Seattle and beyond—is well on its way to changing the world. Banded together we became an unstoppable force capable of anything. We founded a nonprofit. We started this magazine. We grew up.

It’s not just that I love these people—it’s that I need them. I need them to help me find a dentist and convince me to open an IRA. I need them to make me laugh fitfully in silence until my belly hurts, to indulge in fancy martinis and to teach me to see myself in a more forgiving light.

Just a few weeks ago, I was driving back to the city from a wedding with some girlfriends. We giggled and gossiped and talked like sisters, like we’d known each other since the dawn of time. Now and again it hits me that we’re lifers, that these friendships are forever. No matter what.

In the meantime, I’ll be scheming to start our own come-as-you-are Club Med in which we’ll all buy property in some fabulous corner of the world—Taos, Tuscany, Rio, Miami—and build a series of shared homes one villa and flat at a time. I imagine rendezvous in the hills of San Francisco, chance dinners in New York. I see us in the big cities, in the blue yonder, coming together for holidays like all families—our friends, our posse, our tribe.