In one of the wealthiest counties in the United States Ida Farrington, a 59-year-old woman with sugar diabetes and high blood pressure, does not have enough money to fix her hot plate.

In the same county, where the typical family earns $28,500 a year, "Big Walt" Kilkucki, a tattooist who moved last year from South Philadelphia, finds life "very, very depressing." In an adult bookstore, downstairs from his tattoo parlor, a man was hit on the head with a hammer recently when he opened a magazine he should have left alone.

A 19-year-old pouty-faced girl named Dee, who dropped out of school last year in Charlottesville, dances topless in the county where the average home is worth $71,200. Dee makes nearly $300 a week, but last year she made nothing. This summer she bought a butterfly tattoo for her left breast from Big Walt for $20.

The woman with the broken hot plate, the tattooist and the topless dancer all live in Fairfax County along the Route 1 corridor - a strip of asphalt and neon that differs from the rest of Fairfax as K-Mart differs from Bloomingdale's.

The Route 1 corridor runs from the Capital Beltway to Fort Belvoir, cutting between the exclusive subdivisions of Mount Vernon and middle-income housing in Lee District.

Along its seven miles is lined a post-World War II conglomeration of fast-food and cheap-living outfits that exalt themselves in red, yellow, blue and green neon. There are shishkebab joints and weather-beaten shacks, a waterbed store and two fortune tellers, massage parlors and junkyards and a polo field.

"In two minutes," says a fireman at the county's busiest fire station, on Route 1, "we can be at a house worth $200,000 or a shack worth $2,000."

Surrounded by the extraordinary affluence of a county that advertises itself in The New Yorker magazine as the ideal home for corporate headquarters and big-money executives, the Route 1 corridor is a blue-collar ghetto.

Firemen stationed along Route 1 joke that they work in the "South Bronx" of Fairfax County - But the ghetto they joke about is benign compared to those in most East Coast cities. Although there are hundreds of people along the corridor who are forced to ask for free food every month, the average income for the 60,000 people in the area is well above the federal government's poverty level of $6.190. Census figures from 1970, which county planners say still hold true, showed median family income in the corridor at about $13,000.

"These are not terribly poor folks," says Dr. Robert Weigl, a community psychologist at the Mount Vernon Mental Health Center. "If you took the corridor and dropped it in one of the middle-income suburbs outside Detroit, it wouldn't stand out at all.

"But in Fairfax there is a tremendous sense of isolation for the people of the Route 1 corridor," Weigl says.

Warren I. Cikins, the county supervisor whose Mount Vernon District includes part of the corridor, calls the residents of the corridor "invisible" people. "They are the blue-collar people who do the work for those of us who live in the comfortable subdivisions."

Charles Holliday, 61, and his wife Frances, 56, do not live in a comfortable subdivision. They rent a small house for $150 a month that needs paint and sits beside Route 1. In mid afternoon, traffic on the road is so loud that when the Hollidays sit on the porch they must yell to be heard.

Like many of the people who have moved into the Route 1 corridor in the last 20 years, Charles Holliday is a former coal miner. He left Lookout, W.Va., 15 years ago when the mine gave out and now he works for $4.50 an hour at a Holly Farms chicken outlet on the highway.

His wife, who used to clean motel rooms across the road for seven years, now works with Charles at Holly Farms on the same shift and makes $3.75 an hour.

The highway noise, which they say remains loud both day and night, is something to which they have grown accustomed. "After nine years you don't even notice it. We went down to babysit our daughter's dogs in Woodbridge and we couldn't sleep because it was too quiet," Frances Holliday said.

The Hollidays, who have reared four children along Route 1, said schools in Fairfax are better than in West Virginia. "But nothing else much interests me around here because I don't get out of the house," Frances said.

According to psychologist Weigl, who has spent two years working in the corridor, many Route 1 people, like the Hollidays, are isolated by their income and their relatively low social standing in the county.

Many of the "invisible" people in the corridor are whites who moved since World War II to Fairfax from North and South Carolina, West Virginia and Pennsylvania, according to businessmen and county employes who work in the area.

They left coal mines, poor farms and low-paying factory jobs to come to the Washington area because "they hear the salaries are good here," says Eleanor Kennedy, head of United Community Ministries, an organization that feeds and clothes the Route 1 poor.

"What they don't hear about is the cost of living. They think that moving to Washington will answer all their dreams," Kennedy says.

Kennedy, Weilg and other observers of Route 1 say that many of those who find jobs and establish stable lives there remain attached to their rural and industrial homes.

Doan F. Young, 60, a carpenter who has lived in a mobile home near Route 1 for 18 years, plans to go back to Beckely, W.Va., when he retires. Young and his wife Lura, a department store manager, have a combined yearly income of about $25,000.

"Let me tell you it is nothing to save money and live in a trailer. We buy a new car every year and we pay cash. We buy a color TV, no problem," Young said recently as he sat in the trailer that he paid for 10 years ago.

"I still don't like the trailer. It's like living like a gypsy," said Young, who pays $93 a month to park his home. He has been around Fairfax and seen the sumptuous homes in Mount Vernon and Great Falls. "As far as living, those places are a different world. You're not all jammed together like here. That is really nice."

Young, however, says he does not just want a big house, he wants West Virginia.

"I'm a hillbilly. I don't like living around here. The air is dirty. When I'm working on a humid day, I take two steps and I'm all tired out. Up in West Virginia I'm a different person. I can wade those rivers all day and fish and fish."

"In a country where the federal government is the major employer, the corridor's fear of federal "outsiders" reinforces its isolation.

"Some of the people who've lived here for years are very proud and very suspicious," according to Kennedy, who has headed the church and community-supported United Community Ministries four years. "They are suspicious of anything to do with the government. Some would rather suffer than ask for help."

The people of Fairfaven, a moderate-income community of duplexes and single family homes recently rejected a government plan to help them fix up their homes with low-interest loans.

The wariness along Rte., 1 is directed, also, at police and firemen. Fireman W.M. Mitchell remembers helping to free a man pinned beneath a car earlier this month. Mitchell used a suction hose to clean the man's face of blood.

When the man's face was clean, he opened his eyes and spit in Mitchell's face. Later, Mitchell said the man tried to "whip a policeman's tail."

People who live along Route 1 say they do not like county police. Earl Hambleton, who has operated the Tower Inn cabins on the highway for 40 years, says the officers are rough.

"The law enforcement here, they got a conspiracy against the people of Route 1. They just don't like them," Hambleton says.

Police at the Groveton District station on Route 1 refused to talk about law enforcement problems. But Mitchell and other firemen at Company 9 admit there is "no love lost between the people and the police and fire departments.

"The people out here want somebody to baby them," Mitchell said, "but the cops go in and smack 'em on the side of the head, get who they came for and get out."

In March at the One South Restaurant Night Club police were accused of brutality by patrons after a melee in which six people were arrested, several were hit with nightsticks and two were hospitalized.

An internal investigation by Fairfax police cleared the officers of any wrongdoing.

To ease what officials call a chronic housing shortage, the county and the federal government have helped build 700 subsidized housing units in the corridor and another 437 are planned. Nearly $500,000 has been committed in low-interest loans for residents of the Huntington area to refurbish and preserve homes built soon after World War II.

"The corridor definitely has a lot of problems," said Deirdre Coyne of the county's Housing and Community Development Agency. "It's important, first of all, to keep up the existing housing because it is cheap compared to the rest of Fairfax. It [the corridor] is nearly the only area where you can find housing at less than $45,000."

A few communities along the corridor, such as Gum Springs, a largely black area with some residents who can trace ancestry back to George Washington's slaves, have become adept at attracting federal grants. Gum Springs has increased the number and quality of housing, while getting rid of the tar paper shacks that once symbolized the community.

Route 1 has the highest concentration of welfare recipients in Fairfax, according to the county Department of Social Services.

To get at problems caused by poverty, the county has centralized its social service and health department in one building along the highway. The Route 1 Task Force, a coalition of government and volunteer agencies and of people who need help, has pushed for coordination of services for the poor.

There remains, however, problems of alcoholism, broken families, seasonal unemployment and isolation, according to Kennedy of United Community Ministries.

"It is a well-known fact," Kennedy says, "that some of the wealthy people in this county don't want to admit we have poor people."