KANSAS CITY, Mo. -- The Chiefs and Royals announced Friday that both Kansas City franchises would remain in Jackson County, where Arrowhead and Kauffman stadiums are located, if voters there approve the extension of an existing sales tax that has long paid for their upkeep.

The stadiums, which opened in the early 1970s, are located at the Truman Sports Complex and have been tied to each other through lease agreements with the county for the past five decades. But with the current lease expiring in 2030-31, both teams are planning for the future of their facilities, and the Royals have indicated they want a new downtown ballpark.

They would use the extended sales tax to help fund it while the Chiefs would use it for Arrowhead Stadium renovations.

The Royals have been considering bids from Jackson County, where a new ballpark would be close to the existing T-Mobile Center and Power & Light entertainment district, and a competing offer from Clay County, which sits across the Missouri River.

"The Chiefs and the Royals have partnered with Jackson County for 50 years in a partnership that has worked well for all constituents," the teams said. "As part of the proposed agreement between the teams and Jackson County, the teams have agreed to provide more than $200 million in new economic benefits to Jackson County over 40 years in a new lease agreement."

The agreement would alleviate the county's obligation to pay stadium insurance premiums and redirect the park tax back to the county. Meanwhile, the Royals would privately fund a new $1 billion ballpark district around their new facility.

The Jackson County legislature is due to meet Monday, and the Chiefs and Royals will attempt to get the tax on the April ballot. If approved, that would clear the way for both teams to begin planning for construction and renovations.

"The partnership between Jackson County, the Chiefs and Royals has been a tremendous success over the past 50 years, and directly responsible for much of the great momentum our hometown has built," the teams said. "The framework described here is a significant financial benefit for Jackson County, collaboratively built around concerns expressed by the county executive and other local leaders, and provides a further boost to Kansas City and the region for decades to come."