For three or four hours each day, state Sen. Howard A. Denis campaigns door-to-door in the silk-stocking neighborhoods of Bethesda and Chevy Chase. With three months left to election day, the Republican senator has covered more than half the 26 precincts.

In Montgomery County jargon this "shoe-leathering" and "lit dropping" is an inescapable necessity for state Senate and House of Delegates races in Maryland Legislative District 16 the county repository of the best educated richest - and consequently, politicans say, most undependent-minded voters.

It is also the Montgomery County version of the Republican heartland.

Despite a 2-to-1 Democratic lead in voter registration. District 16 keeps electing Republicans in the liberal Republic an tradition of Sen. Charles McC. Mathias Jr., Rep. Newton I. Steers Jr. and former Rep. Gilbert Gude. But Republican candidates in the district rarely emphasize their party ties. In the campaign literature of most District 16 Republicans party affiliation, if stated at all, is buried deep in the brochure.

This year three tireless Republican campaigners are challenging the three Democratic House incumbents in a race considered by Republican leaders as the best target for a Republican entry into the all-Democratic Montgomery House delegation. The only primary contest will be between two Democrats attempting to defeat Denis in his efforts to be reelected to the state Senate.

Bounded by 1-270 and its imaginary southern extension on the west. Wisconsin Avenue on the east and Montrose Road to the north, the 16th District lies just over the District of Columbia line. Its neighborhoods - Friendship Heights, Westmoreland Hills, Somerset and Garret Park to name a few are seedbeds of activism, mainly because of battles against new development.

In addition, Kenwood and a few precincts along the Massachusetts Avenue corridor are Republican territory. "It's rich, rich," remarked an election worker.

Average housing prices in District 16 are farabove the rest of the county and condominium conversions are [WORDS ILLEGIBLE] the few lewer income families near the District at Columbia line. The area is getting older and is losing population (mostly as a result of smaller families) and school closings are a constant threat.

It is also an area where national, not local or state politics, come to many voters' minds when the "issues" are mentioned. In District 16, filled with high-level federal bureaucrats embassy employes and cabinet officials, many voters are more conversant with foreign affairs and federal water policies than with sewer sizes and state pension plans.

"There are a lot of famous people here," said Denis. "Sometimes my eyes pop when I look at the walking list. The other day it was William Colby, George Meany and William Safire. I even asked Safire to autograph his book for me."

In such a community, where national politics is so prevalent, an important means of capturing voters' attention for local and state races is proved civic ties.

In the legislative race this year, the incumb - all have served one-term or less - are stressing their experience while the newcomers are criticizing the persent delegation's performance.

"Assessments in my area went up 47 percent in three years" said candidate. John Perrin, president of a computer leasing firm and a Republican who placed sixth of six in the same race in 1974. "It is our number one problem because it's forcing older people to leave, and the young can't afford to move in." He has proposed that assessments rise only at the rate of the increase in the cost-of-living.

"When I go shoe-leathering the people ask who's in Annapolis and what are they doing for us?" said Connie Morella chairman of the Montgomery College English department who lost the delegate race by only 769 votes in 1974.

Graham Weaver, the 1976 Republican chairman for Gerald Ford in the county and an insurance broker, said that after going to 7,000 homes, "scores of Democrats say they'll split their tickets to elect the best. The issues are running with the Republicans this year."

Perrin, Morella and Weaver are unopposed in the Republican primary for the three delegate seats.

But Democrats Marilyn Goldwater, John X. Ward and Nancy Kopp have consistently purveyed an image of a cooperative incumbent team, sending newsletters to Democrats and Republicans and holding monthly town meetings. "The burden is on our opponents to prove how they could have been more effective," said Goldwater. "We believe we can be more effective as the majority party."

The only promary race in the district is a Democratic contest for the state Senate nomination between Joseph Gebhardt and Ann Ozer.

Gebhardt, a public interest lawyer in Washington and a Udall delegate to the Democratic National Convention two years ago, has emphasized "honest government measures" and the fact that he has considerable party support. Ozer, who has lived in Fdemoor for 14 years, is a mother of five and a founder of the Bethesda Day Care Center. She said she stands for the residents "who haven't been heard. They feel the party is too petty and controlled."