Virginia voters go to the polls Tuesday to help choose a president, elect a senator, decide six contested House races and fill a variety of local offices.

Voters in Northern Virginia also will decide a number of local bond referendums, as well as voting on two state constitutional amendments.

Registration for the election closed on Oct. 6.

Three presidential tickets appear on the state's ballots: President Ronald Reagan and Vice President George Bush for the Republicans, Democrats Walter F. Mondale and running mate Geraldine Ferraro and independent candidate Lyndon H. LaRouche and his running mate, Billy M. Davis.

Republican Sen. John W. Warner, 57, seeking a second six-year term, is opposed by Democrat Edythe C. Harrison, 50, a former legislator and civic activist from Norfolk.

In Northern Virginia, incumbent 8th District Republican Rep. Stan Parris of Fairfax, who is completing his third two-year term, is being challenged by Democratic State Sen. Richard L. Saslaw, an Annandale businessman who is making his first bid for Congress, and independent candidate Donald W. Carpenter.

Tenth District Republican Rep. Frank R. Wolf of Fairfax, first elected in 1980, is seeking his third term in a race against Democratic challenger John Flannery of Arlington, a former federal prosecutor.

In the 7th Congressional District, three candidates are seeking to replace Republican J. Kenneth Robinson of Winchester, who is retiring.

The contenders are Democrat Lewis M. Costello of Winchester, an accountant and businessman, former state legislator Republican D. French Slaughter Jr. of Culpeper, and independent R.E. Frazier of Earlysville.

In addition, voters in Fairfax and Arlington will each choose a member of their county boards. In Fairfax, voters in the Mount Vernon District will select a replacement for former supervisor Sandra Duckworth from among three candidates: Democrat Gerald W. (Jerry) Hyland, Republican T. Farrell Egge and independent Gerald A. Fill. In Arlington, Board Vice Chairman John Milliken, a Democrat, is opposed by Peter Espada, who is running with Republican endorsement.

The statewide constitutional issues, neither of which has become controversial, include a measure that attempts to correct a flaw in the Virginia Constitution to allow interim appointments and/or elections to fill vacancies in the office of mayor