While President Reagan appears on the verge of a landslide reelection victory, the outlook is not entirely bleak for Washington area Democrats.

They have high hopes of picking up two House seats in Virginia, giving them control of the House delegation, even though the president is expected to carry the state easily and Republican Sen. John W. Warner is heavily favored over Democratic challenger Edythe C. Harrison.

And while polls show Reagan ahead of Walter F. Mondale in generally Democratic Maryland, all but one of the state's seven Democratic congressmen are expected to prevail easily. The exception is veteran Clarence D. Long, locked in a tight race with an opponent he has defeated twice, Helen Delich Bentley.

In the District, the key race is the crowded contest for an at-large City Council seat. Republican incumbent Jerry Moore, upset in the primary, is trying to win reelection as a write-in candidate.

Voters also will be considering a wide variety of local ballot issues, from school bonds to shelter for the homeless to allowing the sale of liquor.

Prince George's County residents will determine whether TRIM, the county's property tax limitation, should be modified. A ballot question in Montgomery County will determine whether the county retains its at-large council elections or shifts to a districting system, and voters in Clarksburg, Darnestown and Damascus will decide if they will end the prohibition on sale of liquor in those areas.

A statewide ballot question in Maryland would, if passed, prevent persons barred from voting -- such as former state senator Tommie Broadwater, who recently served four months in jail -- from filing to run for public office.

In Fairfax County, the ballot carries a $74.8 million bond question, for money that would go toward financing the public schools capital improvement program.

Although Reagan has held a consistent lead of about 10 points in Maryland -- new polls in two Baltimore papers published today showed little erosion in his base -- the battle for the affections of the state's 2.2 million voters is regarded by professionals in both parties as narrower than it appears in the public opinion surveys. Final-week campaign visits by three of the four major party candidates, Mondale, Geraldine A. Ferraro and Vice President Bush yesterday indicate that a tight race might be in the offing.

"I always expected the race to be close, and it's still going to be close," said Maryland GOP Chairman Allan C. Levey. Maryland Republicans, who have spent four years in the doghouse after failing to carry the state for Reagan in 1980, are excited over the prospects of once again being welcome in the big house on Pennsylvania Avenue.

In the District, an 80 percent Democratic city that gave the Carter-Mondale ticket 75 percent of the vote four years ago, the contest to fill one of the two at-large City Council seats appears to be as nip and tuck as the presidential contest seems lopsided.

Democratic incumbent John Ray is favored to win one of the two at-large slots, but the other appears up for grabs. Council veteran Moore, after losing the Republican primary to Carol Schwartz, has mounted a vigorous write-in challenge to hold onto his seat. Aided by church leaders and many of Mayor Marion Barry's supporters, Moore is in a tight race with Schwartz and Statehood Party candidate Josephine Butler, who has the support of organized labor.

The District ballot includes an initiative question that if approved would make it official city policy to provide overnight shelter to the homeless, a measure that has been opposed by city officials who fear it would strain the budget and make the city a magnet for those seeking shelter.

Virginia's only statewide race has been from its beginning a lopsided contest with Harrison as the underdog, ignored by some of her own party in her longshot bid to oust first-term Senator Warner. Warner, running this time without his former wife Elizabeth Taylor, appears poised to knock Harrison back to relative obscurity. With little help from her own party, Harrison's campaign has been adrift and taking on water from the beginning. Warner has outspent her 6 to 1, and he is ahead 3 to 1 in the polls.

Perhaps the most interesting feature of the elections in Virginia will be the test of Reagan's coattail effect.

Despite Reagan, Virginia Democrats are optimistic about their chances of reducing the GOP's current 6-to-4 edge in the local House delegation, which before 1982 was 9 to 1 Republican. The Democratic hopes of picking up one and possibly two seats rest in the 7th and 1st districts.

The race in the heavily Republican 7th, which includes Manassas, Charlottesville and Fredericksburg, pits Democrat Lewis Costello, a tax lawyer from Winchester, against Republican lawyer D. French Slaughter Jr. of Culpeper in what is regarded as a close contest to fill the seat of retiring Republican Rep. J. Kenneth Robinson. The campaign resurrected one issue that had not surfaced prominently in years in Virginia when Slaughter was forced to defend his support years ago of the poll tax.

In the 1st District along Virginia's coast, freshman Republican Herbert Bateman faces an aggressive, professional campaign by Democrat John McGlennon, a professor at the College of William and Mary. If Reagan's coattails prove strong, Bateman could survive McGlennon's challenge, which includes one ad picturing his opponent apparently asleep at a meeting.

The Republican challenger in Virginia's 6th District, former state senator Ray L. Garland, is also pinning his hopes on the coattail effect in his bid to unseat first-term Democrat James Olin, who appears headed for a second term in the district that includes Roanoke and Lynchburg. Garland enlivened this campaign by comparing the Democratic Party to a "busted-out $2 whore."

In Northern Virginia, Republican incumbents Stan Parris and Frank R. Wolf are favored to win reelection victories in the 8th and 10th districts. Parris is looking for a strong victory over Democrat Richard Saslaw of Alexandria to boost his gubernatorial hopes. Wolf is expected to capture a third term despite an aggressive campaign by former federal prosecutor and U.S. Senate staff member John P. Flannery II of Arlington, who may learn the limits, at least in Virginia, of trying too hard to appear Kennedyesque.

One of the most hotly contested races in Northern Virginia will decide which party controls the Fairfax County Board of Supervisors, which has been in Democratic hands since Reconstruction. A three-way race for the open seat between Democratic nominee Gerald W. Hyland, independent Gerald A. Fill and Republican T. Farrell Egge could give the GOP control of the board.

Maryland, which has no state-wide races this year, should solidify its reputation as a state that is generous to incumbents. With the exception of 11-term veteran Long, all of the state's incumbent House members have easy races.

Long, who represents the 2nd District, which includes much of Baltimore County and part of Harford County, faces his third straight challenge by Bentley, a feisty Republican who came within 8,000 votes of an upset in 1982.

Bentley got a lesson in the pitfalls of presidential coattails when Reagan hailed her efforts to get the Baltimore harbor dredged during a visit to the city, and then the next day insisted the funds be dropped from a congressional spending bill. A visit by Bush yesterday could help close Long's roughly 5-point lead in the polls and repair any damage Reagan did.

And if all that is not enough for area voters, they can go to bed assured that the gubernatorial races in Virginia (1985) and Maryland (1986) and the mayor's race in the District (1986) will get under way in earnest first thing in the morning.