Rep. Todd Young has garnered 80 percent of the vote with 19 percent of precincts reporting.
Voter turnout in Monroe County so far is about half of what it was four years ago.
Eight legislators are leaving their seats, either to retire or run for another office.
Nine schools districts are trying to pass education referenda in tomorrow's elections to receive more tax money for schools.
Voter turnout is expected to be low in tomorrow's primary because of a lack of statewide races.
Erin Magee is running for Congress in Indiana, Tennessee and Florida.
A Pew Charitable Trusts report shows Indiana has improved its election performance but is still fares poorly compared to other states.
Latest voter registration numbers show 13,000 fewer people are registered for this year's primary than four years ago.
Vigo County plans to replace its 87 precincts with 18 vote centers in the 2014 election.
Indiana saw several changes to its political roster after the 2012 elections.