Statistics via Kentucky State Board of Elections and Jefferson County Clerk

Democrats increased their lead over Republicans in Jefferson County, as more registered voters identified themselves as Democrats during the past year despite the party losing significant ground in almost every other county in Kentucky, part of a decadeslong trend.

Although Republicans gained twice as many registered voters as Democrats in Louisville from October 2016 to October 2017, the tables turned in the past year, as Democrats gained 6,349 voters — over three times the amount of new Republicans.

The Democratic Party still has a large advantage in Jefferson County with 57.2 percent of registered voters, while 32.9 percent are registered as Republicans and 9.9 percent are registered as independent.

This overall registration advantage and the spike during the past year are reasons Democratic Mayor Greg Fischer is thought to be the favorite to win re-election to his third term next month, not to mention Congressman John Yarmuth, who has won blowout victories since first taking his seat in 2006 and whose Third District excludes the most Republican section of east Louisville.

But outside of Louisville, Lexington’s Fayette County and a few low-population counties in eastern Kentucky, Democrats have hemorrhaged registered voters during the past two years, while Republicans have gained a total of over 70,000 new voters for their party.

Statistics via Kentucky State Board of Elections

Republicans have gained 70,748 registered voters since October 2016, decreasing its total in only tiny Owsley County, where they lost 87 voters. While Democrats have gained more voters than Republicans in Louisville and Lexington, they only managed to do so in a few dozen other counties and by margins of less than 150 voters.

From October 2016 to October 2017, Democrats actually saw a decrease in their registered voter numbers in all but 19 of Kentucky’s 120 counties, though that improved to 34 counties during the past year.

Democrats lost nearly 13,000 registered voters last October. Since then until last month, their ranks increased by 3,151 voters, but the party still lost voters outside of Louisville and Lexington, where they gained nearly 10,000 total.

The biggest gain for the Republican Party during the past two years came just south of Louisville in Bullitt County, where the party gained 2,138 registered voters and the Democrats’ ranks decreased by just shy of 1,000.

This slide in registered voters is a decadeslong trend for the Democratic Party in Kentucky, which had a three-to-one advantage over Republicans in the early 1980s. Democrats still had twice as many registered voters as Republicans as late as 1996, but as of September this year, they now have 49.8 percent of voters, compared with the Republicans’ 41.6 percent.

This summer marked the first time in recent history — and perhaps in the Commonwealth’s entire history — that less than half the registered voters in Kentucky were registered as a Democrat.

Partisan registration in Jefferson County has been remarkable stable relative to the rest of the state, as Democrats held a 60 percent to 30 percent advantage over Republicans in 1996, not far from where it stands today.

Republicans have dominated federal elections in Kentucky during the past three decades, taking back the majority of the state House for the first time in nearly 100 years in 2016. Democrats hope to cut into the Republicans’ large majority in that chamber this year — particularly eyeing seats in Louisville and Lexington — although the political trend in most of the state is not in their favor.

Jefferson County gained a total of 4,598 registered voters from October 2016 to October 2017 and 10,059 in the past year.