President Reagan and Walter F. Mondale wound up their presidential campaigns in their home states last night as tracking polls showed Reagan continuing to hold a comfortable lead over Mondale, while a late Washington Post-ABC News Poll indicated voter movement toward Democratic candidates in congressional races.

Reagan, ending the last campaign of his career with a nostalgic tour of California and a 25-minute television speech aired nationally, said his work in Washington "has only just begun" and contended that the conservative "prairie fire" he promised to light 20 years ago has swept the nation. Details, Page A12.

"It was the second American revolution, and it's only just begun," he said. He added that his first priority for his second term would be "peace, disarmament and the reduction of world nuclear weapons." He called the Democrats the party of "torpor, timidity and taxes."

Mondale, cheered by more large crowds and indications that he might be gaining on Reagan, insisted, "We're gonna win." Details, Page A12.

Campaigning in Los Angeles, Mondale urged his audiences to deny Reagan a "historic mandate" and to bring about "the biggest upset in history." He also expressed his pride in his historic decision to put Geraldine A. Farraro on his ticket. "I'm proud of it, I'm proud of her and I'm proud of opening that door for our country," he said.

The Post-ABC News Poll of 2,212 people taken Saturday through Monday showed Reagan's margin over Mondale at 14 points, 54 percent to 40 percent. Over the three nights Reagan's lead varied between 12 and 14 points in samples of varying size. This was down from 18 points in a poll completed Thursday.

In House races, the three-night tracking polls indicated movement toward the Democratic Party. The three-night average showed that respondents favored the Democrats by 48 percent to 45 percent, but last night's sample showed a larger move toward the Democrats, which tended to confirm what Democratic officials said they found in their polling.

Reagan campaign officials said their nightly tracking poll showed the president with a 19-point lead over Mondale on Sunday night, while Mondale's internal polling put Reagan's lead at 14 points.

Other pollsters also disagreed. The final Harris Survey, completed Sunday night, put Reagan's lead at 12 points, 56 to 44 percent. Harris, who earlier had said there was a substantial surge toward Mondale, yesterday predicted that Reagan will win "a substantial victory." The latest New York Times-CBS poll, however, indicated that Reagan's lead was 21 points. A survey for USA Today had it at 25 points.

Reagan's tracking polls, his aides said, showed him with a lead of less than 10 points in just seven states. The closest, according to Reagan-Bush officials, were Minnesota, where he was leading Mondale by two points, and Pennsylvania where his lead was five points. He leads in Maryland by six points, in New York and Iowa by seven points, and in Illinois and Massachusetts by nine points, his aides said.

Of Harris' finding, Reagan's pollster, Richard B. Wirthlin, said, "I'd be surprised if it the president's lead were that low. I think we're looking at 57 percent to 61 percent of the vote for the president."

At midnight voters in tiny Dixville Notch, N.H., cast the first presidential ballots in nation, giving Reagan a 29-to-1 lead.

In North Carolina, Sen. Jesse Helms (R) and Gov. James B. Hunt, his Democratic challenger, are in a virtual tie, according to the latest polls. So are Sen. Charles H. Percy and his Democratic challenger, Rep. Paul Simon (D), in Illinois. There essentially has been no movement in the polls in either race recent days.

Democrats said that if the North Carolina race is that close, Hunt's strong organization could carry him to victory today.

Campaign officials for both parties said they believe that Rep. Tom Harkin of Iowa will retire Republican Sen. Roger W. Jepsen and that Massachusetts Lt. Gov. John F. Kerry (D) is pulling away from businessman Raymond Shamie (R) in their fight for the Senate seat being vacated by Sen. Paul Tsongas (D).

The Republicans also contend that John R. Raese, their candidate in the race for the West Virginia Senate seat being vacated by Sen. Jennings Randolph (D), has pulled even with Gov. John D. (Jay) Rockefeller IV. Reagan's polls indicate that he has an 18-point lead over Mondale in that normally Democratic state, according to his aides.

Democrats also have hopes that a late surge for their candidates will enable Mondale to carry some states where polls show him trailing badly and make their underdog Senate candidates competitive as well.

Despite poll evidence to the contrary, Texas Democrats say that increased registration of blacks and Hispanics and a concentrated get-out-the-vote campaign give them a chance to carry that state for both Mondale and state Sen. Lloyd Doggett, who is running against Democrat-turned-Republican Rep. Phil Gramm for retiring Republican Sen. John G. Tower's seat.

Republicans nourish similar hopes in the Senate races in Nebraska and Kentucky, where incumbent Democrats J. James Exon and Walter D. Huddleston, respectively, hold 10-point leads over their challengers, Nancy Hoch and county judge Mitch McConnell.

The Democrats contend that their tracking polls indicate that their net loss of House seats will be considerably less than the 26 seats the Republicans need to win to offset their losses in the 1982 elections. Both parties are placing a great deal of importance on the House races this year because the Republicans' losses two years ago cost them their ideological working majority in the House.

Democratic Congressional Campaign Committee officials contend that they will lose less than a dozen House seats, but their Republican counterparts claim they'll win at least 20.

The Democrats say that Social Security is beginning to settle in as an issue as many voters fear that the Republicans will cut Social Security benefits and want Democratic members of Congress to protect the program.