THANKSGIVING is the annual reminder that, even in a country as rich as this one, a steady supply of groceries is not to be taken for granted. North America is the only continent that has never known famine, and that is not the least of the attributes that make the United States different from other countries--more secure, more confident in itself, more optimistic. Americans have understood from the beginning that this extraordinary bounty places special responsibilities on them. That is the Thanksgiving tradition, along with the turkey and the pumpkin pie.

For most people, it is a family celebration. This year, it arrives to find a great many families without much to put on the table, and some without any table at all. Washington is better insulated from the recession than most cities. But the numbers of homeless families here are rising at a frightening rate, according to Fred Taylor, who sees a lot of them. He provides some of the energy that runs a deeply useful organization called Hope and a Home, which works with families in the temporary shelters to help them stick together and find more permanent places to live. Its current newsletter notes that the number of families in the city's shelters has risen from around 50 a night last July to about 200 currently. As Mr. Taylor observes, people's unemployment benefits are running out.

The Community of Hope runs a shelter for families at 14th and Belmont streets NW. Thomas Nees, a minister in the Church of the Nazarene, who serves there, says that the need for this kind of help is rising rapidly. Today, the Community of Hope will serve Thanksgiving dinner at the shelter to 150 of its friends and the people in the neighborhood with whom it has been working.

Hopkins House, in Alexandria, vigorously carries on the settlement house tradition, and its executive director, Anice C. Wilson, reports that many people are now coming in "whom we've never seen before." Hopkins House always holds a Thanksgiving dinner, and it expects a couple of hundred people today. Mrs. Wilson says, "It's a delightful, joyous day."

Many dozens, and perhaps hundreds, of dinners like those are being given today in and around this city. The people who give them all seem to have the same impressions--that distress has become much more widespread in the past few months and, this time, the reasons are not very complicated. It's a simple lack of paychecks.

Thanksgiving marks the harvest and, in those parts of the country that produce the food, there's a somber mood. This year, the harvests have been all too good and, under the weight of huge crops, prices have fallen even lower than last year's depressed levels. This country remains very rich by any standard. It has plenty of food to feed the hungry. But this autumn, more than for many years past, unprofitable surpluses are piling up on the farms while, in the cities, too many Thanksgiving dinners are being left to the settlement houses and the churches.