Always friendly to a candidate who looks good in a cowboy hat, particularly if he is a Republican incumbent, voters in the Rockies and points west yesterday gave President Reagan and his Republican Party an even more substantial victory than in his 1980 western landslide.

Network television projections gave Reagan victory in all 13 western states and showed easy wins for Sens. William L. Armstrong (R-Colo.), James A. McClure (R-Idaho), Pete V. Domenici (R-N.M.), Ted Stevens (R-Alaska) and Alan K. Simpson (R-Wyo.).

Four years ago, Reagan lost Hawaii's four electoral votes to President Jimmy Carter and won every other western state by margins of 10 to 52 percent.

This year, even Hawaii, rich in union support and run by a Democratic Party juggernaut, joined the rest of the region in the Reagan column to demonstrate its traditional support for any White House occupant.

With 111 electoral votes at stake in the West and more to come after the next census, the Democratic Party did its best in the campaign's closing weeks to bring its message to the Pacific Coast, hoping to show that a Republican could not adequately represent the area's peace, environmental and women's movements.

Much to the astonishment of some of his advisers who considered the president's home state a certain loss, Mondale campaigned strenuously in California, and Ferraro appeared to make headway at rallies in California, Oregon and Washington. But it was to no avail.

With exceptions such as southern Oregon and northern Idaho, most of the West has recovered nicely from a recession that never bit as deeply there as in the rest of the country.

In much larger proportions than in the East, westerners own their land and homes, drive private cars and use guns. Their interest in government-supported public services and support for government regulations and taxes was habitually less strong than in the East, making them attractive targets for the GOP's limited-government message.

Given a well-organized, high-spirited effort to return Reagan to the White House, even marginal Republicans in the West took heart during this campaign.

Washington Gov. John Spellman (R), among the few endangered top GOP incumbents, wrestled with a reputation for indecision and the regional distress about failed nuclear plants and rising electricity bills. But he was thought to be catching his opponent, Pierce County (Tacoma) Executive Booth Gardner (D).

In Oregon, Sen. Mark O. Hatfield (R), briefly sidetracked by a controversy over his and his wife's relationship with a Greek financier, defeated underfinanced state Sen. Margie Hendriksen (D).

Utah State House Speaker Norman H. Bangerter (R), whose constituents adore his avuncular manner, buried Democratic hopes even deeper by recapturing his state's governorship.

In California, with no statewide races on the ballot, Republicans directed their energy toward trying to upset a powerful band of well-entrenched Democratic congressmen by passing a new plan for redistricting in 1986 by an independent commission.

The Democrats' brightest spot in the West appeared to be Montana, where the networks declared that Gov. Ted Schwinden and Sen. Max Baucus were reelected. Alaska

Reagan led the Republicans to a sweeping victory in a turnout so heavy that the vote count was unusually late. Senate Minority Leader Ted Stevens (R) spent much of his campaign against former state attorney general John E. Havelock helping GOP candidates in other states.

Stevens noted that he had won previous races with 70 percent of the vote and said, "I have no reason to doubt that this year will be any different."

Democratic Party Chairman Willie Hensley noted in defeat that he had trouble raising funds, especially when Ferraro decided not to visit.

The only serious contest was for the lone House seat. Six-term incumbent Don Young (R) had a 10-point lead in late preelection polls against Pegge Begich (D), widow of former representative Nicholas Begich (D), killed in a 1973 plane crash. A former Democratic national committeewoman, Begich criticized Young's congressional attendance record in her campaign aimed at undecided voters. Arizona

Reagan carried Arizona easily, holding a better than 2-to-1 margin with about half of the vote counted.

With no races for the Senate or governorship to consider, voters focused attention on the race for the 5th Congressional District seat representing Tucson and the eastern part of the state.

Rep. James F. McNulty Jr. (D) and former state senator Jim Kolbe were in a tight battle, trading the lead. The race had featured a down-home folksy appeal by both sides.

Reagan did a personalized radio commercial for Kolbe, one of 20 candidates aided that way nationwide by the party. That was partly to soothe GOP feathers ruffled last month when Vice President Bush canceled a visit to help Kolbe in order to see what proved to be the final game of baseball's World Series.

Reps. Eldon Rudd (R) and Morris K. Udall (D) faced no opposition in the 4th and 2nd districts, respectively. California

The state's former governor, now president, won by a strong margin, the challengers to two entrenched Democratic members of Congress were threatening upsets and party squabbles were all in the past, but Republicans last night worried about a close vote on the unique, seemingly innocuous Proposition 39.

After several unsuccessful ballot measures and court fights, the California GOP made a last attempt to overturn the redistricting masterpiece of the late Rep. Phillip Burton.

Burton carved out districts with such care that Democrats took 28 virtually safe seats of the 45 in the House, despite a much closer ratio of Democratic to Republican votes in the last few elections.

Under Proposition 39, redistricting powers would be taken from the Democratic-controlled state legislature and given to a commission of retired judges.

Millions were spent on this and other propositions enjoying success in early returns. Proposals to end bilingual ballots and institute a state lottery held strong early leads, and a plan to close loopholes in tax-cutting Proposition 13 was also winning.

An energetic GOP registration campaign and steady growth in numbers of upwardly mobile suburbanites gave the Republicans an edge of 740,000 to 656,000 in the summer race for new voters.

In what were expected to be the closest congressional races, early absentee-ballot returns usually favorable to Republicans showed Rep. Jerry M. Patterson (D) trailing former representative Robert K. Dornan (R), while Rep. George E. Brown Jr. (D) led insurance man John Paul Stark (R). Rep. Ronald V. Dellums (D) trailed in early returns. Colorado

Reagan won on a Rocky Mountain high, as he did in 1980. As votes were tallied, he was expected to run so strongly here that even the state's former presidential hopeful, Sen. Gary Hart (D), might not have carried the state against the president.

In the Senate race, incumbent William L. Armstrong (R) was declared winner of a second term just after polls closed. The campaign of his opponent, Lt. Gov. Nancy Dick (D), never really got off the ground.

With almost one-third of the vote counted, the GOP was on its way to a 4-to-2 advantage in the congressional delegation by winning the House seat being vacated by Rep. Ray Kogovsek (D).

In that race in the huge Western Slope district, former state representative Michael L. Strang (R), a rancher who attended Princeton University, was running well ahead of environmental activist W Mitchell (D), former mayor of Crested Butte.

Mitchell's may have been the nation's most defiant candidacy. He has campaigned energetically despite being confined to a wheelchair because of partial paralysis suffered in a plane crash and has severe facial scars after being burned in a motorcycle accident.

A casino-gambling referendum in Pueblo was also expected to lose, but the odds were even on a statewide referendum to bar use of state funds for abortions. Hawaii

In 25 years of statehood, Hawaii has never sent a Republican to the House of Representatives and, through last night, Democrats controlled both U.S. Senate seats, the governorship and 64 of 76 state legislative seats.

Despite this, Hawaii supported another incumbent president, not surprising given the intense patriotism of retired and active military personnel and Japanese-Americans who comprise the state's largest voting bloc.

The two congressional seats remain safely Democratic. Idaho

Reagan romped, as predicted, and Sen. James A. McClure (R) won a third term. The suspense dealt with whether the president would win more than 70 percent of the vote in the competition with Utah as his best state. In 1980, he won here with 66 percent, while Utah delivered 73 percent.

In the 2nd Congressional District, convicted felon Rep. George Hansen (R) was holding a substantial lead in early returns in his hard-fought rematch with right-leaning Ricks College professor Richard Stallings (D), who almost defeated him in 1982.

The bearish, folksy Hansen, who has failed in four attempts to reach the Senate, has won all of his House races since 1964 despite often spirited opposition and a string of financial and ethical problems. These culminated this year when he was convicted of four felony counts for violations of the Ethics in Government Act and was formally reprimanded by his House colleagues.

Hansen's most recent strategy has involved comparing his offenses with Ferraro's financial-disclosure problems in hope of persuading voters that he is the victim of a double standard. He is appealing his conviction. Montana

Reagan was declared an easy winner in the state where Mondale lost to Sen. Gary Hart (D-Colo.) in the spring primary election and never recovered, even though Hart subsequently campaigned in Montana for him.

Republicans hoped that Reagan's victory would be big enough to help Senate candidate Chuck Cozzens (R) overcome the sizable lead of Sen. Max Baucus (D).

But Baucus, who spent a record $1.1 million, handily defeated businessman Cozzens, while Libertarian Party candidate Neil Halprin, an attorney, was a distant third.

Popular Gov. Ted Schwinden (D) won a second term, defeating state senator Pat M. Goodover and Libertarian Larry Dodge. Reps. Pat Williams (D) and Ron Marlenee (R) also won. Nevada

At the top of the ticket, the state known for gambling and night life gave a victory to Reagan, candidate of the staid, fundamentalist right.

The president had been the odds-on favorite in the state of his campaign chairman, Sen. Paul Laxalt (R). But the two-member House delegation appeared to be remaining bipartisan, as expected.

First Congressional District incumbent Rep. Harry Reid (D), a lawyer and former state gaming commission chairman, was defeating registered nurse Peggy Cavnar (R).

A statewide ballot initiative to limit taxation also appeared to be winning. New Mexico

Reagan and two-term Sen. Pete V. Domenici (R) swept to victory by large margins in a state that once held promise for Democrats, who have a 3-to-1 edge in voter registration.

Early returns showed Domenici, chairman of the Senate Budget Committee, swamping challenger Judith A. Pratt (D), who upset the state Democratic chairman in the primary. She was expected to be a scrappy challenger, bolstered by the "Ferraro factor," but the vice-presidential candidate never campaigned here and Pratt never got geared up.

Rep. Bill Richardson (D) is a freshman from a district created in 1982 as a Democratic safety zone, and it apparently worked. Richardson was leading Louis H. Gallegos (R), a former Domenici aide. The two Republican incumbents also were on their way to retaining their House seats, as expected.

Reagan won in a landslide here in 1980, but Democratic candidates did well two years ago. This has been a battleground for the Hispanic vote, but Mondale was leading only slightly in the latest polls of that group. Oregon

Reagan took the state's seven electoral votes despite victory predictions by Mondale and Ferraro and their major campaign courtship of the state's numerous independents.

Democrats were bucking Reagan's last-minute decision to sign a timber contract-relief bill called crucial by the hard-pressed Oregon lumber industry, the state's biggest employer.

Sen. Mark O. Hatfield (R), who sponsored the timber bill, weathered a campaign-funding brouhaha over his and his wife's dealings with a Greek financier and defeated liberal state Sen. Margie Hendrikson (D), who complained of inadequate funding from national party headquarters.

In one of the nation's biggest-spending House races, Rep. Les AuCoin (D) narrowly led businessman Bill Moshofsky (R) in the 1st Congressional District with about half of the vote counted.

Rep. Denny Smith (R) was leading repeat challenger state Sen. Ruth McFarland (D) in the 5th District. Reps. James Weaver (D), Ron Wyden (D) and Robert F. Smith (R) were reelected. Utah

Voters in this overwhelmingly Republican state had elected Democratic governors for two decades, but the Reagan surge -- confirmed by an early victory projection -- and an unusually adept GOP candidate ended that string.

State House Speaker Norman H. Bangerter (R) easily defeated former U.S. representative Wayne Owens (D). Bangerter, like retiring Gov. Scott M. Matheson, has an offhand, kindly matter that contrasts sharply with the overly earnest young Republican candidates often encountered by Utahans.

In early returns, former state senator Frances Farley (D), a politician whose door-knocking prowess has produced surprises, was slightly behind Lt. Gov. David S. Monson (R), who had been tarnished by business dealing with a former CIA agent accused of selling secrets to the Soviet Union.

They were contesting the 2nd Congressional District seat of Rep. Dan Marriott, who stepped down in an unsuccessful run for the gubernatorial nomination. Washington

Reagan took the 10 electoral votes, overcoming an all-out effort by the Mondale-Ferraro campaign. Ferraro, however, was very popular in a campaign that focused on Washington's economy, where recovery has lagged compared with the rest of the nation.

In one of the nation's hottest gubernatorial races, Pierce County (Tacoma) Executive and timber millionaire Booth Gardner (D) appeared to have defeated first-term Gov. John Spellman. Gardner was so shy and unaccustomed to campaigning that his voice was described in print as sounding like "Elmer Fudd on helium."

Former television commentator John Miller (R) easily defeated former Audubon Society head Brock Evans (D) for the 1st Congressional District seat of retiring Rep. Joel Pritchard (R). Incumbents in the other seven districts were easily reelected. Wyoming

Reagan was winning almost 75 percent of early returns. If he made some voters nervous, what with planning to move the MX missile in and making their state a higher-stakes target in any nuclear exchange, Mondale and his liberalism made them even more so.

The state's lone House member, Rep. Dick Cheney (R), was winning easily despite the mild heart attack he suffered earlier this year.

Incumbent Sen. Alan K. Simpson (R), co-author of the Simpson-Mazzoli immigration bill, defeated Victor A. Ryan (D).