Growth is a hot topic in this year’s local elections and a major component of just about every key discussion in local politics.

But just how fast is Orange County actually growing?

“We doubled our population in the last 30 years, (and) we’re expected to double it again over the next 40,” said Chapel Hill-Carrboro Chamber of Commerce president Aaron Nelson during his annual State of the Community report last week.

View the full report here.

According to the 2010 census, Orange County’s population was a little less than 134,000. Today that’s roughly 140,000 – and by 2020, we’re projected to add another 20,000 residents, for a total of 160,000.

And the number keeps growing from there: nearly 200,000 by 2030, more than 230,000 by 2040, and more than 277,000 by 2050 – or about twice what our population is today.

Nelson says nearly all of that growth will be in the cities. By 2050, Chapel Hill will have a population of 114,000, about twice what it is today; Hillsborough will double from 6,000 to 12,000 residents; and Carrboro’s population will more than double, from about 20,000 today to more than 50,000.

But there’s a fourth municipality as well.

“The big surprise is Mebane,” Nelson says. Mebane today has about 1,800 residents – but given current projections and development plans, Nelson says that’s expected to balloon to more than 42,000 by 2050, more than twice the size of Carrboro today.

“And this is the Mebane of Orange County,” Nelson says. “This is not all of Mebane –  this is the Mebane piece in Orange County that’s expected to grow to 42,000 people.”

That’s in a space of just two square miles, a third the size of Carrboro.

But while all that growth may sound daunting, Nelson says it’s important to keep it in perspective. For one thing – for better or worse – Orange County is not expected to grow nearly as fast as the Triangle’s other counties.

“In Wake County, someone was telling me, 50 people a day are moving in – (that’s) an elementary school classroom a day,” Nelson says. “We are growing dramatically slower – we will only take 5-7 percent of the total population growth expected for the entire Triangle.”

And while all that extra population will make our towns a lot denser, Nelson says Chapel Hill and Carrboro are not nearly as dense as many of the other college towns with which we like to compare ourselves.

“Chapel Hill in 2030 (will still be) less dense than (present-day) Boulder, Ann Arbor, Burlington, and Charlottesville,” he says.

Still, Chapel Hill is going to become significantly denser than we’re used to. In 2030, Chapel Hill will have nearly 4,000 residents per square mile. To put that into perspective, Carrboro today contains a little more than 3,000 residents per square mile – and that’s the highest population density of any town in the state.