Developers and investors are pouring an increasing amount of capital into commercial and residential real estate projects in the Bronx, looking beyond the portions of Brooklyn and Queens where prices have skyrocketed, to gamble on what some are saying is the next outer borough hot spot.

With easy commutes to Manhattan, lower prices than other boroughs, and development sites ripe for the picking, sources said “frontier” neighborhoods like Mott Haven, Hunts Point and Port Morris are generating new interest at all levels.

The dollar volume of investment sales in the Bronx last year rose above $2 billion, a 39% increase from 2013, and a 55 percent jump from 2012.

It’s clearly a bargain. With land prices ranging from $45 to $60 per buildable square foot, the Bronx is considerably cheaper than Manhattan, downtown Brooklyn and Queens neighborhoods like Long Island City.

Last year alone, dollar volume of sales increased by 88%, to $130 million in the neighborhoods of Hunts Point, Melrose, Mott Haven, Morrisania and Tremont. Over 40 transactions took place, comprised of 73 properties with 2 million buildable square feet.

Neighborhoods like the Hub, a major retail center located in the Melrose area in the heart of the South Bronx, where East 149th Street and Willis, Melrose and Third avenues converge, are reaping the benefits of the renewed interest.

In a little more than a year, Old Navy, The Gap and Planet Fitness moved in, along with two new boutique hotels.

There are hints that gentrification is already taking hold in this neighborhood.

Once a piano district, Mott Haven — area bordered by East 149th Street, the Harlem River, the Bronx Kill and the Bruckner Expressway — is undergoing a gradual refresh and renewal. Plans are in motion for hundreds of rental units along a stretch of the Harlem River where Jordan L. Mott, for whom the area was named, once made iron stoves and other items.

The developer Pinnacle Real Estate Ventures rehabbed three buildings on Alexander Avenue and rented all six three-bedroom units at market rate (they start at $2,400 a month).

Other development projects have taken root around Bruckner Boulevard, a largely industrial area that was rezoned twice in 1997 and 2005. Nearby, Carnegie Management plans to break ground this summer on a 130-unit rental building with an indoor pool while the JCAL Development Group plans to start construction this spring on two side-by-side rental buildings, with 15 units, on Alexander Avenue near Bruckner.

“I think Mott Haven has all the makings of the next Williamsburg,” said Marlene Cintron, president of the Bronx Overall Economic Development Corp. “There are new developments, restaurants, rehabbed buildings and an easy commute to Manhattan.”

At the Mott Haven Bar & Grill, specialties already include quinoa black bean burgers and Israeli salads; a restaurant called Ceetay offers Asian fusion food; and a soon-to-open coffee shop nearby will double as a tapas bar.