When we talk about thriving startup communities, we often talk about “New York” and “the Bay Area” (or less so, “Silicon Valley” and “San Francisco”, but this is lazy shorthand. We don’t mean the Upper West Side, or the Financial District, or Harlem. We don’t mean Outer Sunset, Oakland, or Sausalito. Thriving startups may exist in any of these areas, just as they may exist in North Dakota, but they are not the hubs of activity.

Brad Feld discusses the significance of this, observing that serendipity in Boston’s startup community happens in Cambridge, not in “Boston”. While other, smaller startups hubs exist, Cambridge, with its proximity to Harvard, MIT, and other successful startups creates a critical mass.

You would think that with the massive financial resources of New York, any location in New York would be good for a startup, yet there is a reason that the pulse of the startup community emanates from the Union Square / Flatiron area. Startups weren’t always prominent in the city of San Francisco – for a long time, the locus of innovation sat many miles south in Silicon Valley. When startups crept up into the city, they didn’t start everywhere – they started in SoMa.

Startups need EVERY advantage they can find. It can be easier to work from home. It can be cheaper to work from some outer suburb. When I started working on Badgy full-time last summer, I began spending some days working for free in a local ad agency’s warehouse space in a sparse industrial neighborhood, and some days working from Tech Square, a midtown Atlanta area right next to Georgia Tech and quite close to ATDC, one of the oldest startup accelerators out there. When we spent 5 months in Georgia Tech’s Flashpoint Accelerator, this happened even faster. I still stop through there regularly – there are TONS of serendipitous opportunities, and it’s a 2 minute walk from our HQ.

The difference was night and day. Working from the agency meant a slightly shorter commute and unbelievable proximity to an awesome korean taco joint, but that was about it. When I worked from Tech Square, people who have changed the trajectory of my company passed through shared offices I worked from. I’d run into these people walking down the street, or set up a future meeting with someone I ran into during another lunch meeting.

In a world where email, mobile phones, and video chat connect people instantly, it’s easy to underestimate the value of physical proximity. Boulder, Colorado has a thriving startup community, driven by startup density. In Atlanta, we would just call Boulder a suburb – it’s as close to downtown Denver as many of Atlanta’s outer suburbs are to downtown. I am certain that if an entrepreneur claimed that putting their office in Denver was just as good as setting up in Boulder, they would be roundly chastised, but in Atlanta, we pretend that all locations are equal, and that spreading startups across our metro area’s 8,000 square miles is competitive with Boulder concentrating its startups into 40 square blocks.

Any startup community that wants to replicate Silicon Valley, New York, Cambridge (Boston), or Boulder cannot ignore these facts. Proximity matters. Not linearly. Exponentially. Imagine that raising your seed round isn’t a matter of getting introductions to people you’ve never met. Imagine it’s having follow-up conversations with people you were first introduced to when you met a friend for lunch, then ran into them half a dozen times as you walked down the street to other meetings, then you talked to them about investing.

It’s easy to look at the Bay Area with its multiple startup communities and believe that your city can accomplish that same thing. In reality, you can get there, but before you can succeed in multiple areas, you have to find a way to succeed in one neighborhood. Series of serendipitous meetings add up to meaningful outcomes. Stubbornly trying to succeed 5 minutes from your house isn’t startup suicide, but your chances of success are remarkably higher in a thriving startup community.

If you’re near a startup hub neighborhood, embrace it. If you’re not in a startup hub, help lead your community by identifying a neighborhood with a chance to become a hub and embrace it. Don’t work from your neighborhood, an irrelevant suburb, or a slightly cheaper vacuum. Your startup needs serendipity – communities accelerate serendipity.