Developers looking to cater to younger generations are increasingly building massive mixed-use developments. Holistic, “live-work-play” hubs of strategically combined multifamily and commercial buildings are effective uses of space in what often are dense urban environments where land is at a premium.

Greg Freedman, co-founder of development firm BH3, told Commercial Property Executive recently that mixed-use properties also represent a “‘stronger-together,’ recession-resistant formula,” noting that the hottest markets for mixed-use developments are those with high-growth populations, cities with high volumes of STEM (science, technology, engineering, math) interests, economies geared toward creative businesses and so-called “24-hour” cities like New York, Miami and Los Angeles.

Many up-and-coming mixed-use plots around the country are the centerpieces of cities’ bids to be the potential site for Amazon’s HQ2, which should be assigned a location by year-end.

Construction Dive compiled a list of six of the largest mixed-use developments underway now, as well as a mammoth proposed project. This list excludes mixed-use developments built around sports venues, since that market is significant enough to warrant a list of its own.

Port Covington — Baltimore, Maryland

Cost: $5.5 billion

Developer: Weller Development

Components of this massive development, to be anchored by Under Armour’s headquarters, include:

• 250-unit residential building with ground-floor retail.

• 180,000 square feet of office space.

• An approximately 156,000-square-foot hotel.

• 42,000 square feet of retail space.

• 13,000 square feet of market space.

Weller Development’s request for proposals for an architect for the residential piece and general contractor for the remainder of the project were due earlier this year. Development of the 260-acre site is still in the permit phase and developers must complete water, sewer and road infrastructure before construction can begin.

Bonds, supported by future incremental tax revenues the development will generate, will help pay for the estimated $1.4 billion worth of infrastructure upgrades. When construction begins, likely in 2020, it could generate up to $9.4 billion in construction-related economic activity and create 54,000 related jobs throughout its estimated 25-year timetable.

The Gulch — Atlanta, Georgia

Cost: $3 billion to $5 billion

Developer: CIM Group

Components include:

• Nine high-rises.

• 9 million square feet of office space.

• 1 million square feet of retail.

• 2,100 apartments.

• 1,500 hotel rooms.

This 27-acre “mini-city” is reported to be the largest development Atlanta has seen since the 1960s. Each high-rise will be at least 225 feet tall, with one already planned to reach the 500-foot mark.

CIM Group could be the recipient of $1 billion to $2 billion in public financing, depending on how much development it’s able to bring to the downtown area known as the Gulch. Although speculation abounded when plans were unveiled that the developers were soliciting Amazon’s HQ2, Bisnow reported CIM Group and local officials are talking with other companies, including a Fortune 500 company, interested in relocating to the Gulch.

Schuylkill Yards — Philadelphia, Pennsylvania

Cost: $3.5 billion

Developers: Brandywine Realty Trust and Drexel University

Components of this 14-acre development, which will include 7 million square feet of new construction, include:

• Eight high-rises.

• 6.5 acres of planned green space and street improvements.

• 4.6 acres of residential, office, research and retail development.

• Revamp of the Bulletin Building.

Developers expect the entire buildout, which they say will be a “hub of innovation with the park at its center,” to take up to 20 years to complete. In an effort to develop small businesses, affordable housing and jobs, Brandywine also is spending nearly $6 million to launch a community program.

Water Street Tampa — Tampa, Florida

Cost: $3 billion

Developer: Strategic Property Partners

Components of this 53-acre, 9 million-square-foot development include:

• 3,500 total residences.

• 2 new hotels, in addition to renovations at the existing Marriott Waterside Hotel.

• Retail space.

• Approximately 1 million square feet of office space

• University of South Florida’s Morsani College of Medicine and Heart Institute.

Scheduled for completion in late 2019, the medical facility will be the first of the 18 total buildings to open in this development, which will take nine years to finish. The developers — a joint venture between Bill Gates’ Cascade Investment and NHL team Tampa Bay Lightning’s owner, Jeff Vinik — are planning to pursue WELL certification for the entire development, a standard that focuses on building features that impact the health and wellness of their occupants.

River District — Chicago, Illinois

Cost: $2.5 billion

Developer: Tribune Media

Components of this 30-acre project include:

• Up to 14 mixed-use buildings.

• 5,900 residential units.

• Retail and office space.

• 13 acres of public space.

The Chicago Plan Commission signed off on the development in October. New construction will total 9 million square feet with buildings not to exceed 650 feet in height and a public promenade that will span the length of the site’s waterfront. Construction on the first phase, which will include four residential buildings, will begin in 2020 and could generate up to 19,000 jobs. The development could attract 7,400 residents to the previously protected industrial land.

To handle the expected increased population density, the Chicago Department of Transportation is pushing for transport infrastructure improvements, which could someday include a light-rail line connecting North Side neighborhoods and downtown commuter stations, reported the Chicago Sun-Times.

Riverton — Sayreville, New Jersey

Cost: $2.5 billion

Developer: North American Properties

Components of this 418-acre development along the Raritan River include:

• Retail and dining venues.

• Office space.

• Three hotels with a total of 700 rooms.

• Parks and a marina.

• A food hall with locally sourced and international offerings.

• More than 1,000 luxury waterfront residences.

• 2 miles of waterfront.

Situated on one of the state’s largest brownfield remediation efforts, construction on this 5 million-square-foot development will last through 2021. The developer believes the community, which it’s dubbing as “New Jersey’s next great hometown,” will cater to millions of visitors each year and create tens of thousands of jobs. The location, only a half hour from New York City, sits at the convergence of three major interchanges.

Plus one to watch:

Lincoln Yards — Chicago, Illinois

Cost: $5 billion

Developer: Sterling Bay

Components of this 53-acre project include:

• 5,000 new residences.

• 500 hotel rooms.

• 20,000-seat soccer stadium.

• 800-foot-tall high-rise.

• More than 13 acres of open space.

Encompassing more than 12 million square feet of new buildings, this project — if it sees the light of day — could create 2,500 construction positions during each of its first 10 years of building. Potentially transforming as this project is, though, Chicago Alderman Brian Hopkins said at a public meeting in July that “it’s as far from a done deal as you can get.”