Several east metro cities also have contested races for mayor.
A longtime Washington County commissioner trailed in her bid for reelection with three-quarters of precincts reporting in District 4.
Autumn Lehrke, a Cottage Grove small business owner, was leading Myra Peterson, a strong advocate for public transportation and vulnerable residents. Peterson has served on the County Board since 1993.
By late evening in two other County Board races, incumbent Bill Pulkrabek was leading Dean Johnston in District 2, and incumbent Lisa Weik was leading Kelly Monkman in District 5.
In the race to represent Cottage Grove and surrounding cities and townships, Lehrke, 28, criticized Peterson as making a career out of her County Board service and said fresh ideas were needed. Peterson, 71, countered that her longtime experience meant her constituents were represented well in county government.
In Ramsey County, the two challenged commissioners who represent St. Paul neighborhoods coasted to victory. Toni Carter defeated Rory Koch with about 74 percent of the votes in the District 4. In District 5, Rafael Ortega won with a nearly 2-to-1 margin over Andy Noble.
A third incumbent, Janice Rettman, ran unopposed in District 3.
In east metro city races, Woodbury will have a new mayor for the first time in 17 years because Bill Hargis announced in April he would not seek reelection.
With 40 percent of precincts reporting, outgoing City Council Member Mary Giuliani Stephens was leading a field of six candidates.
Woodbury also was home to the county's most crowded City Council race, with 16 contenders for two seats: the one currently occupied by Giuliani Stephens and that of Julie Ohs, who sought reelection.
With 40 percent of precincts reporting, Ohs and Christopher Burns were the top two vote-getters.
Also in Washington County, Oakdale Mayor Carmen Sarrack and Stillwater Mayor Ken Harycki each faced challengers. Sarrack led with 63 percent of the vote counted.
Stillwater residents faced a familiar choice: Harycki or City Council Member Dave Junker. They faced off in 2006 when Harycki was elected. With nearly half of the votes reported, Harycki held a slight lead.
In Forest Lake, three candidates are vying for the top job after four-year Mayor Stev Stegner declined to seek reelection. With 40 percent of the vote tallied, Chris Johnson held a slight lead over Jackie McNamara.
In Ramsey County, Arden Hills and Roseville will see new mayors.
With 25 percent of precincts reporting, Council Member David Grant was leading the Arden Hills mayor's race. Dan Roe won the Roseville mayor's seat with 78 percent of the vote.
KEVIN GILES AND Emma Carew