The shift is especially consequential in Highlands Ranch, where state Senate District 30 is contested this year. Republican Sen. John Carson, who won a January 2025 vacancy election, faces Democrat Kevin Leung. Both have served on the Douglas County School Board, where control has swung between conservative and Democratic-aligned members in recent elections.

Carson has raised about $130,000 and loaned his campaign $36,500, according to campaign figures cited in the report. Leung has raised about $132,000 and loaned his campaign $50,000. Outside groups have already spent heavily to support Carson: the Republican-aligned Senate Majority Fund has put nearly $923,000 into the race, while the Republican State Leadership Committee has spent about $40,000 opposing Leung. The leading Democratic Senate independent expenditure committee reported $1.2 million on hand as of Sept. 30 but had not yet spent on Leung.

Democratic state Rep. Bob Marshall, also of Highlands Ranch, is seeking a third term against Republican Nate Marsh. Marshall was the first Democrat elected to represent Douglas County in the state House, winning in 2022 by just over 400 votes. He won again in 2024 by 1,373 votes. This year, Marshall has raised more than $116,000 in cash, loans and in-kind contributions, compared with nearly $67,000 for Marsh.

Democrats took control of the Douglas County School Board again last year, winning four seats to add to the three they already held. The board’s elections are formally nonpartisan, but campaign alliances and spending have reflected the county’s partisan divide.

Voter registration figures show the clearest change is not a sharp increase in Democratic registration, but growth among voters who decline to affiliate with a party. From September 2022 to September 2026, the county’s registered Democrats fell by about 2,000 and Republicans by about 3,000, while unaffiliated voters rose from 119,794 to 147,359. The county’s population has grown from more than 357,000 in 2020 to roughly 400,000.

Republican state Sen. Lisa Frizell of Castle Rock and Douglas County Democratic Party chair Meg Furlow both pointed to newcomers as a major force behind the changes. Frizell said people are drawn to the county’s schools and public safety, while Furlow said growth in communities such as Sterling Ranch has brought voters from Denver, including people priced out of the city.

“I definitely think the Democrats have momentum right now coming off the home rule win, and then taking back the school board last year,” Furlow said.

Frizell warned that the school board could swing again, citing concerns among some residents about a board resolution affecting charter schools and the possibility of renewed teachers’ union influence.

The county’s changing politics has not erased the Republican advantage in federal races. In 2024, Republican U.S. Rep. Lauren Boebert defeated Democrat Trish Calvarese by about 1,000 votes in Douglas County, even as Boebert won the broader congressional district by roughly 52,000 votes. Political observers cited in the report expected Republicans to retain the congressional seat.

Marshall said the opportunity for Democrats lies partly with voters who have left the Republican Party. “It’s not turning blue,” he said. “It’s turning less red.”