MALTBY — Carousel Ranch is about to take a new turn.

For 80 years, the hilly property on Highway 9 has served as a horse farm.

This fall, Snohomish County reached a deal to buy the property, which has belonged to the Curtis family since 1980. The deal will allow a horse-boarding business run by family members to stay there for another year and a half, as the county performs outreach and starts to design a future park.

What sold county staff on the property? Like many real-estate deals, location, location, location.

Carousel Ranch sits on a busy highway, adjoins a rail corridor that the county hopes to acquire and touches the grounds of King County’s Brightwater treatment plant to the south.

“One of the nice things about the Carousel Ranch is that it’s right off of Highway 9,” said Russ Bosanko, operations manager for county parks. “It fits our long-term plan to have the rail and trail connecting on the east side of the property. Also, because it connects to the Brightwater property, we’d hope to have our property connect with the Brightwater trail system.”

The $9 million deal closed Oct. 30. The agreement allows family members to stay in their longtime home on the property and pay rent. Parties to the sale include companies run by the family.

Money for the purchase comes from a $70 million settlement that Snohomish County reached with King County in 2005 over the effects from Brightwater. Snohomish County must use some of the money to build a park within four miles of the treatment plant. Immediately north, at 21815 Highway 9, Carousel fit the bill.

Future amenities at the property are likely to include fields for youth soccer, football and lacrosse, Bosanko said. Walking trails could connect to three miles of existing trails on the Brightwater grounds.

The developed area would cover about 25 acres of the 65-acre site. Other elements, such as a dog park or a children’s spray pad, would depend on available space and what county staff hear from the public.

“It’s a little hilly, so we’ll probably do some kind of tiered build-out,” Bosanko said.

The new parkland touches the Eastside Rail Corridor. County staff had been negotiating to buy a 12-mile segment of the corridor that runs between the city of Snohomish and Woodinville for $5 million, but put negotiations on hold this past spring. Complications include ownership issues in some areas as well as problems with accommodating rail along with foot and bike traffic over some bridges.

The county had hoped to use the corridor to connect its Centennial Trail to King County’s Sammamish River and Burke Gilman trails. Freight operations would continue.

The Port of Seattle owns the rail corridor and has sold off other pieces between Woodinville and Renton.

The Carousel purchase will replace the Wellington Hills property the county bought from the University of Washington in 2012. The county started planning for a park on the former golf course, but faced strong opposition from neighbors.

At more than 100 acres, Wellington provided more space than Carousel. It sits at 6920 240th St. SE, east of the Woodinville Costco.

A sale of the Wellington property to the Northshore School District is pending. The district is looking for space to build new schools for its growing student population.

The $11.2 million price Northshore is willing to pay would cover what Snohomish County spent to buy the land plus the cost of design and engineering reports. A condition of the sale is resolving a lawsuit that Woodinville filed against Snohomish County over the park plans.

Noah Haglund: 425-339-3465; nhaglund@heraldnet.com. Twitter: @NWhaglund.