It takes a village to raise a child, the old proverb says.

Turns out it also takes one to help an adult age.

In all corners of the United States, people who are growing older are turning to villages — virtual villages, that is — for support. Need a ride to the doctor? Someone to watch the cat while you're on vacation? The village can help. Social outings, meals, movies, and seminars? Depending on the virtual village, all of that can be available to members, as well.

Born out of Boston's Beacon Hill neighborhood in 2002, virtual villages have rapidly spread across the country in recent years as another twist on the peer-to-peer economy. Now, with more than 200 villages in 45 states and Washington, D.C., plus 150 more villages in development, according to the national Village to Village network, virtual villages have become a forceful movement to help offset the social and financial housing challenges facing many aging residents.

There are three villages in Philadelphia, as well as one in Springfield, Delaware County. Two are in development in South Jersey.

The idea is relatively simple: Seniors who choose to "age in place," meaning they remain in their homes as they grow older, can pay an annual fee to join a virtual village, if available in their area. From there, members can access numerous resources — everything from ride services to social outings to educational information — all of which are typically run by volunteers. The membership fee and services offered vary by village.

Started as a grassroots movement by seniors themselves, these villages offer one solution to a senior housing dilemma arising across the country as demographics and housing preferences change. Americans are living longer, staying healthier, and want to reside longer in their homes. According to a study by the nonprofit AARP, 90 percent of people who are 65 and older say they want to age in their own homes.

Part of the reason for that age-in-place preference, senior housing advocates say, is a desire for familiarity, comfort, and greater financial freedom. One-third of adults 50 or older are considered "cost-burdened" because they pay 30 percent of their income on housing, and almost a quarter of homeowners in that demographic pay more than 50 percent for shelter, according to a 2014 report by the Joint Center for Housing Studies at Harvard University.

As a result, finding affordable 55-plus complexes, assisted-living facilities, or nursing homes can be a significant challenge. Aging-in-place advocates say villages can fill the gap.

"We try to do anything that a neighbor would do for somebody," said Jane Eleey, 72, executive director of Penn's Village, the virtual village for the greater Center City area. "… But we're not a home health-care agency; we're not a social-service agency. We're a neighborhood organization of folks who want to remain in the community and want to be supportive of each other."

Here is a look at Philadelphia's villages. None is limited to seniors who are 65 and older.

Boundaries: Washington Avenue to "South of Girard" (not including Fishtown), and from the Schuylkill  to Front Street.

Cost: There are three tiers — (a) $600 a year per household to become a "Villager" to receive all benefits, including three services each week from volunteers, such as free rides. (b) $200 a year per household to become a "Neighbor," to receive two services per year, access to social outings, and a list of all recommended providers for local services, such as household repairs. (c) $100 a year per household to become a "Contributor," to receive access to the provider list and educational workshops. Subsidies are available for some potential members.

Membership: 350 members.

Services: Volunteer services such as transportation and companionship outings — including lunch or movie excursions, or keeping a member company at home. Workshops several times a month on topics ranging from smartphones to Medicare. Social events, such as book discussions and tai chi exercises. Access to a preferred provider list, and more.

"If there's a way we can do it, we try to figure it out," Eleey said. "I had someone who wanted to play French Scrabble — we found someone who could play and we hooked them up. … We have somebody right now who has early dementia … and we found a peer who goes out with her for movies and lunch."

"We're not the complete answer, but we're often part of the answer," she said. "Sometimes we can be the complete answer, depending on the health and welfare of the person and their cognitive ability."

Boundaries: The 19129 zip code.

Cost: $125 a year for an individual and $175 for a household. The village also offers need-based financial assistance and allows for "emeritus members," for former East Falls residents who want to stay connected to friends. Emeritus memberships are $75 for an individual and $100 for a household.

Membership: 200 members, including 125 households.

Services: Transportation to medical appointments or pharmacies, for example. A recommended list of providers for local services, such as household repairs. A technology team that makes house calls to help with cell phones, computers, and gadgets. Social events, including lunches (typically two a month), happy hours, weekly yoga, neighborhood tours, and educational programs. Village members also have the opportunity to read to children at the Thomas Mifflin School in East Falls.

"Part of the important thing about our village and a lot of villages is that you're building community," said Mary Flournoy, 71, co-chair of the village with Phil Hineline, 77. "Even if members lived on the same block for years, they have been working for most of that, so they meet new people in the community that they never met before. We're building a community among ourselves, and we're also reaching out to help the community as a whole."

Boundaries: Neighborhoods along Germantown Avenue and nearby communities. Most membership comes from East and West Mount Airy, Chestnut Hill, and Germantown, though "a few people from Center City find our approach more congenial," said Faye Ross, president of the village. Boundaries are flexible.

Cost: $125 a year for an individual and $175 a household. Subsidies and a scholarship fund are also available for reduced fees.

Membership: 145 members, including 120 households.

Services: A cat care co-op. Transportation services to doctors appointments and elsewhere. Technology assistance. Numerous social events, such as film discussions, book clubs or parties such as "Nostalgia Night — Food of the 1950s." ("Everyone thought of Jell-O right away!" said Ross.) Educational events on such topics as gardening and taxes. A referral list for other helpful organizations.

"People [who retire] find that the friendships they made through their work are no longer working for them and they feel isolated," Ross said. "Or they moved here to be near their children and they have to start all over again. … You don't realize you could use some help."