When Nancy Barbour, legislative assistant to Rep. Herbert E. Harris II (D-Va.), walked into the office on the morning of Nov. 5, the day after the seizure of the American hostages in the U.S. Embassy in Iran, the phone was already ringing.

In Harris' office and the offices of other local members of Congress, the phones haven't stopped ringing since. In the last three weeks, literally thousands of area residents have telephoned their congressmen or sent letters or telegrams expressing their outrage over the takeover. The House postmaster reports the mail volume has increased by 20 percent, while Western Union says the number of telegrams sent to Congress has doubled over the same period.

The verdict from the deluge has been virtually unanimous: The United States should not let some "little two-bit country like Iran" -- as one writer called it -- push it around.

"The people who were calling were saying that everybody who's Iranian should go home or be deported," Barbour recalled yesterday. "They'd call up because they could yell at me and get out some of their frustrations. I've been with Mr. Harris for five years and I don't ever remember an outpouring like this."

Reactions in other offices was the same.

"our calls have been on a scale of over 100 calls a day," said Keith Haller, administrative assistant to Rep. Michael D. Barnes (D-Md.). "It's very heavy. The only thing close to it (in the past) is the reaction we got to the gas crisis this last summer."

"It's been just an overwhelming wave," said Jean McDonald, press aide to Rep. Joseph L. Fisher (D-Va.). "We get them right after the (television) news, first thing in the morning, after they've read the paper, (and) after they've heard the news on the radio on their way home, and after they've had a martini. It's been amazing."

Almost without exception, those who have contacted the offices of their representatives have proposed that the United States take a hard line in dealing with the Iranian government.

"I don't think we've had one caller saying, 'Send the shah back,'" said Haller, whose boss, Rep. Barnes, counts three hostages among his Montgomery County consitiuency.

He shuffled through some of the letters his office has received. "Here's what they're saying: 'Iranian student demonstrations are disgusting . . . Deport all of them.' 'Kill the ayatollah.' 'Send in the Marines.' There's a lot of emotion here. They're not going to accept this (kind of treatment of the United States) any more."

The tone of the letters ranges from reason to outrage. "I would strongly suggest that we declare total war on Iran since they have already in effect declared war on our country," wrote one Forrestville man to Rep. Gladys Noon Spellman (D-Md.). "Should the hostages be harmed a large portion of the population of Iran should be used for much-needed bayonet practice."

"We must do something," wrote a woman in Randallstown to Sen. Charles McC. Mathias Jr. (R-Md.). "That something should be the immediate deportation of the so-called Iranian students . . . Send them back to the ayatollah. He is welcome to them. They are not welcome here."

Rep. Harris was told by one woman, a Woodbridge resident, that "I feel we must take stronger measures to let the rest of the world know the U.S. cannot be manipulated in this manner."

"These are angry, frustrated people, all very upset by the American loss of image," said Paul Samuel, an aide to Sen. Paul S. Sarbanes (D-Md.). "We have 500 letters here now. Last week we were getting 50 letters and telegrams a day."

"We've had over 1,000 calls and letters and not one of them was in support of Iran," said Jack Eddinger, who works for Sen. Mathias. "This is the only time we've ever had a fully negative outpouring about anything."

Congressional aides say Congress has refrained from injecting itself into the situation because of the delicacy of the ongoing negotiations for the release of the 49 Americans still held hostage.

Yesterday, in part in response to the letters and phone calls his office has received, Mathias asked Americans to write letters to Iran's religious leader, Ayatollah Ruhollah Khomeini, to demonstrate this country's unanimout opposition to the takeover.