The first of four smaller, "flexible-format" Target stores opened Wednesday in Center City, marking Target Corp's first foray into a market that's key to its urban push.

The opening of Target Express at 1126 Chestnut St. at 7 a.m, attracted the millennial demographic - aged 19 to 34.

"We have been extremely busy all day," said manager Alex Defeo, 24, just after 5:30 p.m., as the after-work crowd began filtering in to explore the latest addition to the Washington Square West neighborhood. "We've had a lot of millennials. They're happy with what we have to offer, and I think we'll fit well in this urban environment."

The store has the trademark red bulls-eye symbol on the outside. Inside, it had everything that much bigger Targets have, just downsized, including a Starbucks Coffee bar, a CVS Pharmacy, and mini-sections, including a "market" in the middle of the store for groceries, a "home" with pillows and towels, and a "tech" area with prepaid phones and iPhone cases.

Three more Target flexible-format stores will be rolled out in the city over the next 15 months.

The Target planned at 1900 Chestnut St. is to open Oct. 5, and another one will open in October 2017 at 2001 Pennsylvania Ave., near the Philadelphia Museum of Art.

Just announced is a smaller Target, at 47,000 square feet, planned for March 2017 in the Upper Roxborough section.

"Target has been attracted by the city's growing downtown residential population, which has expanded more than 25 percent since 2000," said Lauren Gilchrist, vice president and director of research for Jones Lang Lasalle in Philadelphia.

She said other big-box retailers, including Lowe's and Whole Foods, have entered American downtowns recently.

"In addition to millennials, empty-nesters and high household incomes exceeding $107,000 annually, on average, in core neighborhoods make this the right time to enter a market where household car ownership rates are low and declining. And the live-work-play dynamic is extremely strong," she said.

Larry Steinberg, an executive vice president at CBRE Inc., who brokered the deal to bring Target to 1126 Chestnut, said, "Target's biggest impact will be on the East Market corridor, where the traffic that they create will benefit all the surrounding retailers that have suffered there for years."

East Market is considered one of the city's historic retail corridors and there are several large projects underway to revive it.

John Connors, president of Brickstone Realty, is behind a project on the 1100 block of Chestnut Street that will provide 112 luxury apartments. He said Washington Square West was already home to more millennials per acre than any other area in Center City, and that the new Target will greatly contribute to the quality of life with its broad assortment of merchandise.

"Target is a great addition to the neighborhood," said Dan Killinger, managing director at National Real Estate Development, which is building the $600 million East Market project between 11th and 12th, and Market to Chestnut Streets, that will include residential, retail and office spaces.

"With the variety of shopping and dining experiences opening in this area, there will be something for everyone," he said. "We are excited to see significant interest and investment east of Broad Street, and it can only mean great things for Philadelphia."

As she entered the new store, Allison McCartin, 32, was thrilled. The mother of a 2-year-old lives 10 blocks away and works a block away from it as president of the Epilepsy Foundation for Southeastern Pennsylvania.

"It's super-convenient," she said as she made a beeline to home furnishings. "It's one-stop shopping."

215-854-4184 @SuzParmley