ON A RECENT Friday afternoon, kids screamed with joy as they played in the Liberty Lands park in Northern Liberties. Their parents hung out on blankets with grapes and other picnic goodies.

A few blocks away, at the bustling Piazza at Schmidts, twentysomethings lounged at the plaza tables, brought out their own folding chairs or sat at tables at the nearby restaurants watching Villanova play George Mason in the frenzied NCAA basketball tournament on the plaza's large TV screen.

Rock music popped from the PYT burger joint. Young parents with toddlers strolled by.

The Northern Liberties neighborhood - once a sooty industrial area with tanneries, breweries, cigar factories and gunmaking shops whose workers lived nearby in cramped trinity houses - has become a destination for artists, hipsters, families with young children and single professionals.

This was the "only neighborhood that had so much available land and empty buildings and was so close to downtown," Matt Ruben, president of the Northern Liberties Neighbors Association, said recently.

"A lot of people, including artists who got priced out of Old City, moved up here," he said.

The neighborhood's magnetism over the past several years is credited in large part to developer Bart Blatstein, who invested heavily, buying land and building attractive apartments and trendy restaurants and shops, helping to drive up real-estate demand.

According to census data released earlier this month, Northern Liberties grew by 2,121 residents from 2000 to 2010, or a 60 percent gain, to a total population of 5,635.

Northern Liberties also added about 1,500 housing units over the decade - thanks mostly to Blatstein's developments and the Waterfront Square condominiums - giving it nearly 3,500 in 2010, about 84 percent of which were occupied, according to census data.

A real community

Christina Mastroianni and her husband, George Milton, moved to Northern Liberties from Old City in 2000. Old City "had gotten too crowded," she said, as they sat on a blanket in the Liberty Lands playground, on 3rd Street near Poplar, with their children, Makai, 7, and Marissa, 4.

"The bars were getting too loud," she said. "We wanted to get away from the insanity of Market Street."

In contrast, in Northern Liberties, it's "real quiet" and there's a sense of community, she said. But it "wasn't until we had kids that we really realized how amazing the neighborhood was."

There's a baby-sitting co-op, an email list for moms and a community-run park, she gushed.

The 2.1-acre park - where kids run and parents push them on swing sets, where a community garden grows and where musicians perform on a little stage - was the site of the former Burk Brothers tannery, a huge leather factory that closed in 1962.

The Northern Liberties Neighbors Association, starting in 1995, when it first got the land, worked hard to ensure it was environmentally safe, then planted trees and gardens and kept a wide space for open grassland.

Mastroianni, 41, credited the neighbors association for keeping the neighborhood "clean and green."

Besides the park, she enjoys walking to the shops on Liberties Walk between 2nd and 3rd streets, a Blatstein development, and eating at the restaurants there, such as Bar Ferdinand and El Camino Real.

Mastroianni estimated that her house, purchased for about $70,000, is now worth about $400,000. "We always joke we can never afford this neighborhood now," she said.

Ruben also moved to Northern Liberties from Old City in 2000 because his Old City "rent was higher and the neighborhood was getting noisier."

"I found an amazing community here," said Ruben, 42.

The combination of artists and young people starting families, of homeowners and renters, of garden space and bars, restaurants and shops, is all what works well and sustains Northern Liberties' growth, he said.

Young and hip NoLibs

Young people love how Northern Liberties is a walkable community with hip restaurants and free parking.

Jared Miller, 26, programs coordinator for the Philadelphia Film Festival, was hanging out with friends at the Piazza at Schmidts watching the Villanova game; the weather was in the 70s and the open-air Roman-style plaza was bustling.

In 2009, Miller moved into a house on Orianna Street bought by his friend and shared with two other pals.

The piazza, another Blatstein development, on the former Schmidt's Brewery site from 2nd to Hancock Street and bordered diagonally by Germantown Avenue, has a great farmers market to buy meat and produce, Miller said.

As he described the benefits of the neighborhood - its walkability, friendly atmosphere and closeness to public transportation and Center City - he apologized for losing his train of thought.

"I get distracted by the people-watching," he said amid the thriving foot traffic in the piazza.