The South belonged to Ronald Reagan when voters went to the polls in 1980, and he tightened his grip on it yesterday, carrying one state after another into his column.

All 13 southern states lined up decisively behind Reagan in yesterday's balloting, giving him every one of the region's 143 electoral votes.

In every state, the president was winning by larger margins than he achieved four years ago.

In North Carolina, Sen. Jesse Helms (R) won his acrimonious, $22 million battle with Gov. James B. Hunt Jr. (D). The Republicans also captured the governorship in that state as Rep. James G. Martin (R) outdistanced Attorney General Rufus Edmisten (D).

A big upset seemed to be brewing in Kentucky, where Mitch McConnell (R), a well-financed conservative judge from Louisville, was leading Sen. Walter D. Huddleston in his bid for a third term.

The Republicans lost Senate Majority Leader Howard H. Baker Jr.'s seat in Tennessee to Rep. Albert Gore Jr. (D), but managed to hang on to an open seat in Texas. There Rep. Phil Gramm (R) won the seat of retiring Sen. John G. Tower (R) in a $12 million battle with State Sen. Lloyd Doggett (D) -- the second most expensive Senate race in the nation.

Elsewhere in the South, three other Senate Republicans and five Senate Democrats won reelection.

Southern Republicans have been making impressive inroads in Congress since Sen. Strom Thurmond of South Carolina bolted the Democratic Party in 1964.

Going into yesterday's elections, the GOP held 12 of the 26 Senate seats from the South. The House delegation was still heavily Democratic, by more than 2 to 1, but the Republicans had 39 of the South's congressional districts while the Democrats held 90 others.

In governors' races, the Republicans had nothing to lose. The Democrats held a 12-to-1 advantage in southern governorships on Election Day.

Though the Democrats lost a governorship in North Carolina, they hung on in Arkansas, where Gov. Bill Clinton (D) won handily over Woody Freeman (R), a contractor from Jonesboro.

Tight House races were scattered throughout the South, but North Carolina had the most. There the GOP was predicting the ouster of at least two House Democrats and hoping to pick up three more seats on the heels of a big Reagan victory in the state.

In Oklahoma, by contrast, the GOP seemed to be falling short in its effort to unseat House Budget Committee Chairman James R. Jones. The Tulsa Democrat was locked in a tight battle with former U.S. attorney Frank Keating (R), but Jones edged into a slim lead with more than 90 percent of the vote counted.

The Mondale-Ferraro ticket's slim hopes in the South had been based initially on a big turnout by black voters, many of them new registrants who had come out in support of Jesse L. Jackson during his bid for the Democratic nomination. But as Election Day approached, voter registration among whites also surged. Alabama

Reagan grabbed 60 percent of the vote to take Alabama's nine electoral votes, despite Mondale's support from one of the strongest labor organizations in the South and from black leaders and teachers.

But Sen. Howell Heflin (D) won a second term by a 2-to-1 margin over former representative Albert Lee Smith Jr. (R). Democrats captured five House seats and the Republicans, one. One race was too close to call.

Freshman Rep. Ben Erdreich (D) overcame a strong challenge from former state representative J.T. (Jabo) Waggoner (R), a former Democrat who got some help last week from Vice President Bush. With almost all the vote counted, Erdreich was leading with 60 percent of the vote.

Another Republican convert, former state senator H.L. Callahan, held a narrow lead over attorney Frank McRight (D) in the gulf coast district of retiring Rep. Jack Edwards (R). Arkansas

Reagan captured about 60 percent of the vote to take Arkansas' six electoral votes, but his coattails weren't long enough to pull in Republican challengers for the Senate and governor's mansion.

Both Sen. David Pryor (D) and Gov. Bill Clinton (D) won reelection by margins that appeared to be slightly larger than the president's.

Pryor won a second term, defeating Rep. Ed Bethune (R) with about 60 percent of the vote, while Clinton turned back contractor Woody Freeman (R), a political newcomer, with about 65 percent of the vote.

In the race for Bethune's House seat, a law-and-order sheriff, Tommy Robinson (D), held a commanding lead over state Rep. Judy Petty (R), an outspoken conservative known as a tough campaigner.

In other House races, Democratic incumbents Bill Alexander and Beryl Anthony Jr. and Republican incumbent John Paul Hammerschmidt won reelection easily. Florida

The presidential candidates virtually ignored Florida this year because Reagan carried the state by a landslide in 1980. He did it again last night, capturing 21 electoral votes.

The president's coattails, however, did not appear to be producing any changes in the state's congressional delegation, where Democrats had 12 of the 19 seats going into the election.

In south Florida, Rep. Daniel Mica (D) of West Palm Beach won reelection over spirited opposition from Don Ross (R).

In another contest that had been expected to be close, Rep. Larry Smith (D) of Hollywood appeared to be headed to a comfortable victory over former state representative Tom Bush (R) of Fort Lauderdale.

Rep. Andy Ireland of Winter Haven, who switched to the Republican Party in July, won reelection. Georgia

President Reagan won Georgia's 12 electoral votes by a wide margin, despite former president Jimmy Carter's efforts on behalf of his vice president. With about a fourth of the vote counted, Reagan had an 18-point lead.

Sen. Sam Nunn (D) easily won reelection in his race against school teacher Jon Michael Hicks (R). But Rep. Elliott H. Levitas (D) appeared to have been upset by Patrick L. Swindall (R). With 85 percent of the vote counted, Swindall, a lawyer and owner of a retail furniture business, held a comfortable lead. Kentucky

Sen. Walter D. Huddleston (D) was losing a closely fought battle against Mitch McConnell (R). With more than 80 percent of the vote counted, in McConnell led the two-term senator by about five points. McConnell, 42, a conservative judge, had stressed his support for Reagan and his opposition to higher taxes.

Reagan won the state and its nine electoral votes by a comfortable margin.

The only open House seat was won by Carl C. Perkins (D), the son of Carl D. Perkins, the 18-term incumbent who died in August. Perkins led his opponent, businessman Aubrey Russell, by about a 3-to-1 margin. Louisiana

Reagan swept to victory, collecting 10 electoral votes as state's residents turned out in large numbers for what essentially was just a vote for president.

Sen. J. Bennett Johnston (D) and all eight House members -- six Democrats and two Republicans -- won reelection Sept. 29 when they captured more than half the votes in the state's nonpartisan primary. Mississippi

Sen. Thad Cochran (R) won his race for reelection against former governor William Winter (D) by a wide margin.

Reagan easily won the state's seven electoral votes. Mondale had been expected to collect about 90 percent of the black vote in the state, but Reagan piled up a big margin of white voters.

Cochran, meanwhile, was expected to draw about 20 percent of the black vote -- enough to assure him of another term.

In the race for the seat for the 2nd District, which was recently redrawn to include more blacks, incumbent Webb Franklin (R) held a narrow lead over state Rep. Robert G. Clark (D), with about a third of the vote counted.

Three well-known House incumbents appeared to be headed for victory: G.V. (Sonny) Montgomery (D) was unopposed; Jamie L. Whitten (D) was leading independent John Hargett and Trent Lott (R) was ahead of Arlong (Blackie) Coate. North Carolina

Republicans swept through North Carolina with Reagan easily taking the state's 13 electoral votes and Sen. Jesse Helms (R) defeating Gov. James B. Hunt Jr. (D). Another Republican, Rep. James G. Martin, took over Hunt's job.

If Sen. Charles H. Percy (R-Ill.) goes down to defeat in his tight race for reelection, Helms could become the chairman of the Senate Foreign Relations Committee. Helms has opposed a number of Reagan administration diplomatic nominees as being too liberal.

Helms, who took 55 percent of the vote, ran behind Reagan in the state. The president won by almost a 2-to-1 margain.

In the battle to replace Hunt, Martin overcame an early campaign advantage by state Attorney General Rufus Edmisten, a onetime aide to former senator Sam J. Ervin Jr. Martin took about 56 percent of the vote, despite the strong support Edmisten received from the state's sheriffs, who are considered influential in North Carolina's rural counties.

The Republican sweep of the state spread to the fight for House seats, where early this morning six races -- five for seats that had been held by Democrats -- were considered too tight to call. Rep. Ike Andrews (D) faced a tough challenge from William Cobey Jr. (R) and Rep. James McClure Clarke (D) was neck-and-neck with William M. Hendon (R). Rep. Stephen L. Neal (D) was locked in a close race against Stuart Epperson (R); Rep. Robin Britt was trying to hold off Howard Cobble (R), and Rep. W.G. (Bill) Hefner (D) was battling Harris D. Blake (R).

In the fight for the seat that James Martin will is giving up, Democrat D.G. Martin was in a tight race against J. Alex McMillan (R). Together, the two men spent close to $1 million in the race. Oklahoma

When Reagan nearly swept the South in 1980, Oklahoma, with eight electoral votes, gave him his biggest landslide. The Sooners did it again yesterday, giving the president about seven of every 10 votes they cast.

Reagan's popularity fueled Republican hopes of unseating one of their most important targets, House Budget Committee Chairman James R. Jones (D). Former U.S. attorney Frank Keating (R) was locked in a close race with Jones last night, but most of the late-reporting precincts were said to be Jones' strongholds on the north side of Tulsa.

Jones' district hasn't supported a Democratic presidential candidate since 1936, but he has managed to esablish himself as a moderate conservative who has much more in common with his Tulsa constituency than he does with his party's national ticket.

The statewide balloting was a ticket-splitter's delight. Sen. David Boren (D) coasted to a second-term victory over Will E. Crozier (R); his margin could turn out to be slightly larger than Reagan's. South Carolina

Reagan won South Carolina and its eight electoral votes by a margin of nearly 2-to-1, while Sen. Strom Thurmond (R) won his sixth term, at age 81. Thurmond's opponent, political novice Melvin Purvis Jr. (D), had neither the money nor the statewide connections to mount a serious challenge to Thurmond.

One tight House race pitted Ken Mosely (D), who is black, against Rep. Floyd Spence (R) and Libertarian Robert Madden. Last night Spence appeared to be the victor by about 10 points.

Blacks in the state Democratic Party had pressed white Democrats to support at least one black congressional candidate as Jesse L. Jackson, a South Carolina native, had proposed during his bid for the Democratic presidential nomination. Tennessee

The Democrats picked up the Senate seat of retiring Majority Leader Howard H. Baker Jr. with a resounding victory by Rep. Albert Gore Jr. (D).

The contest was one of the most expensive Senate races. Gore won the $4 million battle by a wide margin over his chief opponent, state Sen. Victor Ashe (R). With more than half the vote counted, Gore was leading by almost 2 to 1.

Reagan won the state's 11 electoral votes with ease; in 1980, he had defeated Jimmy Carter by three-tenths of a point.

The Mondale forces had targeted Tennessee as one of a handful of southern states they thought they had a chance of winning.

Ashe tried to turn his nickname, "Bulldog," into a campaign symbol, but he wasn't able to take much of a bite out of Gore's lead. Gore had the advantage of the name of his father, former senator Albert Gore Sr., and a $2.6 million war chest.

The liveliest House race in the state was the battle for the seat Gore was vacating. Former state party chairman Bart Gordon (D) was running against Joe Simpkins (R), a construction company executive. Simpkins campaigned as a "family man," but Gordon, who is single, won despite his involvement in a well-publicized paternity suit two years ago. Texas

Reagan easily won Texas' 29 electoral votes. After Mondale opted not to ask Sen. Lloyd Bentsen to be his running mate, Democrats had pinned their slim hopes of winning the state on a large turnout among blacks and Hispanics. By yesterday afternoon the turnout was described as "moderate to heavy" but that was not enough to carry him to victory.

With Reagan's strong support, Rep. Phil Gramm (R) won the race to replace retiring Sen. John G. Tower by a wide margin. With nearly half the returns in, he was outpolling his opponent, liberal state Sen. Lloyd Doggett, by 20 points.

Doggett had to contend with Reagan's strong support in the state and his close ties to Gramm, who switched parties after he was disciplined by House Democrats for pushing Reagan's budget and tax proposals.

Doggett's attempt to tar Gramm as a mean-spirited budget-cutter appeared to fall flat and his last hope for victory was a large black and Hispanic voter turnout.

Rep. Jack Hightower (D) was defeated in his bid for a six term by attorney Beau Boulter, who had aligned himself with Reagan.

In Texas' 24th District, Rep. Martin Frost (D) was locked in a tight race with Bob Burk (R). Rep. Bill Patman (D) was in a close race with Mac Sweeney (R). Former Tower aide Larry Combest (R) was leading Don R. Richards, (D) a former aide to Rep. Kent Hance, for the seat Hance was vacating. Virginia

President Reagan easily captured Virginia's 12 electoral votes, and Sen. John W. Warner (R) swept to an even bigger victory to lead a Republican drive in the Old Dominion.

Both parties held on to their House seats, with the split remaining six to four in favor of the GOP.

In one race where the Republicans had hoped to gain a seat, Rep. James R. Olin (D) defeated Ray Garland (R) for the Roanoke-Lynchburg House seat that traditionally had been held by Republicans until Olin captured it two years ago.

Freshman Rep. Herbert H. Bateman (R) of Newport News held off an assault by John McGlennon (D), a political science professor at the College of William and Mary, while former state delegate D. French Slaughter (R) defeated attorney Lewis M. Costello (D), a protege of Democratic Gov. Charles S. Robb, for the seat held by retiring Rep. J. Kenneth Robinson (R).