WILLIAMSON, W.Va. (AP) _ A grand jury Thursday indicted two state legislators, the mayor and 13 other political figures in a mountain coal county already wracked by charges of job-selling and drug-dealing by local officials.

One indictment charged a state senator who was a former county commissioner with bribery in the alleged sale of the Mingo County sheriff's job in 1982 for $100,000, and another indictment accused 15 others of violations of state election laws and conspiracy.

The 15 are accused of conspiring with Johnie M. Owens, the former sheriff and former county Democratic Party chairman, and others to influence elections in 1984 and 1986 and law enforcement in the county.

''The indictment charges this group of people with attempting basically to subvert the free election system in Mingo County,'' said special prosecutor James Colburn. ''They conspired ... by illegal campaign contributions, by illegal campaign expenditures, by bribery, by false accounting, and by conspiring to do all these things.''

Mingo County, the site of the Hatfied-McCoy Fued between mountain clans after the Civil War, is a coal-mining county of 37,000 people along the Kentucky border. Williamson, the largest town, has about 6,000 residents.

A federal grand jury indicted several current and former county officials over the past year, including current Sheriff Charles ''Eddie'' Hilbert, in connection with his appointment as sheriff.

Owens, who has pleaded guilty, said he accepted a $20,000 down payment on the $100,000 bribe from Hilbert, then persuaded the three county commissioners to accept his resignation and appoint Hilbert in exchange for half of the bribe.

Former Commissioner Rastie Runyon also has pleaded guilty and will be sentenced with Owens on April 18, the same day Hilbert is scheduled to enter a plea in a drug case as part of an agreement with prosecutors.

In the drug case, authorities say a drug ring openly run by a small-town fire chief, police chief and their families was protected by a web of bribes to officials.

Commissioner Steve Adkins, the only member of the 1982 County Commission still in office, was indicted earlier on one count of bribery. He has denied the charge but is not running for re-election.

The third commissioner, state Sen. H. Truman Chafin, was indicted Thursday with one felony count of bribery.

Arraignment for all defendants is scheduled Wednesday in Mingo County Circuit Court.

Democratic Sen. John Pat Fanning was charged with two counts of bribery, one count of conspiracy and one count of filing false accounts - all felonies - and one count each of making political contributions exceeding the state limits and failing to report political expenditures, both misdemeanors.

Mingo County Prosecutor W. Thomas Ward was indicted on five felony counts, three counts of bribery and one each of conspiracy and filing false accounts, plus two misdemeanors. Williamson Mayor Sam Kapourales was indicted on two felony counts - bribery and conspiracy - and two misdemeanor counts.

Chafin denied having anything to do with sale of the sheriff's office.

''I received no money or benefit as a result of this transaction,'' he said. ''I was not there when the commission voted on these matters, nor did I agree with anyone at any time not to be present at that meeting.''

Fanning was out of his office late Thursday afternoon and was unavailable for comment, a person answering the phone in his office said. Neither Ward nor Kapourales was in his office and could not be reached for comment by telephone.

Also named as defendants are county school board members Paul Sizemore and Robert Simpkins, former Delegates James B. Simpkins, Irvine K.O. Damron, and R. Doyle Van Meter II, County Commissioners Ronnie Rumora and Steve Adkins, former Mingo County Magistrate Joey Kohari, Magistrate Bill Webb, former Circuit Court Clerk Robert J. ''Jack'' Webb, former County Clerk Hugh Wellman and Larry Hamrick, a former school board member and former director of the county's anti-poverty agency.

Also indicted Thursday was Goodwill Motors Inc., a used car dealership at Delbarton owned by former county commissioner and county Democratic Chairman Stewart Justice. Justice was not named in the indictment.

Last week, grand jurors heard testimony from candidates in the 1984 and 1986 primary elections as well as United Mine Workers Local 1440 President Bill Davis and Wally Warden, editor of the Williamson Daily News.

The newspaper has extensively covered the state and federal probes in Mingo County, and Warden provided jurors with background on the makeup of campaign slates in past elections and with information on precincts that have been the site of voting irregularities.

Davis reportedly was questioned about campaign contributions and financial support from COMPAC, the UMW's political action committee.