As Democratic front-runner Hillary Clinton closes in on her party’s presidential nomination, voters in Oregon and Kentucky look likely to give her a boost Tuesday — though Sen. Bernie Sanders (I-Vt.) could claim a moral victory by extending his winning streak in two states seemingly made for a liberal populist.

In Kentucky, Democrats will award 55 delegates to the national convention in Philadelphia on Tuesday. Only registered Democrats will be eligible to vote in the commonwealth’s closed primary. That should be good for Clinton: She’s won the 10 states that have held closed primaries so far.

But Kentucky may represent Sanders’ best chance so far to break Clinton’s winning streak. More than half of Kentucky’s registered voters are signed up with the Democratic Party, even though the state’s election results have hewed decidedly Republican in recent years. That’s an indication of the rightward shift of downscale whites, especially in once union-heavy Coal Country; those are voters who used to call themselves Yellow Dog Democrats.

In neighboring West Virginia, another state where party registration statistics have lagged behind the electorate’s rightward shift, Sanders’ appeal to populism handed him a 15-point win earlier this month.

Both candidates are playing to win in Kentucky. Clinton spent Sunday in Louisville and Covington, and she has rallies planned in Bowling Green, Hopkinsville and Lexington on Monday. Sanders spoke Sunday in Paducah, where his campaign said 1,900 supporters attended a rally.

The largest Democratic stronghold in Kentucky is in Jefferson County, where 327,000 registered Democrats — about 20 percent of the statewide total — live in and around Louisville. Fayette County, where Lexington sits, is the only other county with more than 100,000 registered Democrats. About 50,000 Democrats live in Kenton County, just south of Cincinnati; another 40,000 come from Daviess County, home of Owensboro.

But Clinton and Sanders will have to hunt small pockets of votes in more rural areas, in a state where most of the population lives in smaller communities. Seventy-six of Kentucky’s 122 counties have fewer than 10,000 registered Democrats, and together those voters — 390,000 in all — make up a larger population than Louisville.

Across the country, more Oregon voters are likely to cast ballots than virtually any other state this year. Oregon voters cast their ballots entirely by mail, which has boosted primary turnout in recent years; state elections officials say they’re receiving ballots at about the same rate as in 2008, when turnout reached a whopping 58 percent in the primary.

Turnout has only topped 50 percent in one other primary this year — in New Hampshire, where 52.4 percent of registered voters showed up to vote, according to statistics maintained by Michael McDonald, a University of Florida political scientist who studies voter participation.

Voter registration in Oregon is rising quickly, after the state legislature passed a measure last year automatically registering anyone who signs up for a driver’s license. That law has led to a spike in turnout among voters between the ages of 18 and 29; their numbers are up 21 percent just since September.

Still, the only recent survey in Oregon shows Clinton leading Sanders by a wide margin. The DHM Research poll, conducted for Oregon Public Broadcasting and Portland’s Fox affiliate, shows Clinton ahead 48 percent to 33 percent. Like Kentucky, Oregon holds a closed primary.

Oregon’s electoral history shows a Democratic base divided between three main regions: Portland, the suburbs, and a liberal bastion of university students, all of which account for about a quarter of the vote.

In 2010, the last time the state held an even somewhat competitive statewide primary, 92,000 of the 391,000 Democratic votes came from Portland’s Multnomah County, the state’s largest. Turnout is likely to be especially high in Portland because of an open mayoral seat; state Treasurer Ted Wheeler is likely to win the Democratic primary on Tuesday.

About another quarter of the vote will come from two suburban Portland counties, Washington and Clackamas.

Outside the Portland area, Sanders is likely to do best in Marion, Benton and Lane counties. The Lane County seat, Eugene, is home of the University of Oregon; Benton County government is based in Corvallis, home of Oregon State University; and the state capital, Salem, is in Marion County. Together, those three neighboring counties will account for about 110,000 Democratic votes, more than a quarter of the statewide total.

The remaining 30 counties in Oregon, which together account for the remaining quarter of the Democratic vote, are divided between logging communities west of the Cascade Mountains and high desert and farmland east of the Cascades.

Oregon Republicans will award 28 delegates on Tuesday, with the majority likely to go to Donald Trump. Trump is 103 delegates short of the 1,237 he needs to win the Republican convention on the first ballot, meaning he will not formally reach that threshold until the final five states vote on June 7.

Polls close in Kentucky at 6 p.m. Eastern. In Oregon, ballots must be returned by 8 p.m. Pacific, or 11 p.m. Eastern, but the all-mail system makes ballot-counting notoriously slow.

Correction: An earlier version of this post transposed the names of two counties.