Six Republican state lawmakers called Monday on U.S. Rep. Ben McAdams to join them in opposing the controversial Olympia Hills development planned near Herriman.

With a final vote to approve the 933-acre, high-density project scheduled before the Salt Lake County Council on Tuesday, two state senators and four House members representing that southwest corner of the county released a letter urging McAdams, a former Salt Lake County mayor, to add his voice to theirs in a last-ditch effort to derail the proposal.

“You are in a unique position now, to again do the right thing for your constituents,” lawmakers wrote in letter hand-delivered to McAdams’ Salt Lake City office. “We ask you to join us.”

The one-page letter is signed by Sens. Jake Anderegg, R-Lehi, and Lincoln Fillmore, R-South Jordan; and Reps. Kim Coleman, R-West Jordan, Candice Pierucci, R-West Jordan, Mark Strong, R-Bluffdale and Susan Pulsipher, R-South Jordan.

“You may be the only person left that can convince your successor as the County Mayor and the remaining County Council members that this development is not in the best interests of the citizens we all serve,” lawmakers wrote to McAdams.

In a statement released Monday, McAdams said he continued to oppose Olympia Hills for the same reasons he vetoed the project in 2018, and he urged state and local officials “to go back to the drawing board.”

Two years ago, then-County Mayor McAdams vetoed an earlier version of the development west of Herriman, listening to a huge outpouring of public opposition that came after the County Council approved the project on a vote of 7-1. McAdams, a Democrat, was replaced by Jenny Wilson as mayor when he won a seat in Congress.

Now, a second, revised version of Olympia Hills — with fewer dwellings and detailed standards imposed by county planners on how it would be built and paid for — has been under review by county planners for more than a year and only needs a vote on Tuesday to become county law.

The plans remain a subject of fierce opposition by many residents and elected leaders in nearby Herriman, Bluffdale, Riverton and other nearby cities. They’re worried about the size of the project in that remote, unincorporated corner of the county and its potential impacts on area traffic congestion, overcrowded schools and other aspects of their quality of life.

In his statement issued Monday, McAdams said even though Olympia Hills is a local planning and zoning matter, “my opinion hasn’t changed. I’m still opposed.”

“I encourage state and local officials to go back to the drawing board and work together to fund the necessary transportation infrastructure and make balanced land use and transportation decisions,” he said.

McAdams identified traffic as a specific concern with the revamped plans for Olympia Hills and said he was pursuing federal funding to improve and expand Frontrunner to help address the county’s wider growth-related needs.

After lengthy discussion and two public hearings, zoning changes to allow the revamped Olympia Hills to proceed got an initial 6-to-3 vote last Tuesday from County Council members. A second majority vote in favor of the zoning changes would give developers Doug Young, John Gust and their partners a green light to pursue a first phase of construction.

Although current County Mayor Jenny Wilson does not have a vote on zoning for Olympia HIlls, she has said she is a supporter of housing density and has praised the county’s second vetting of Olympia Hills and its new county design standards.

Wilson, a Democrat, has also said the project “will be approved.”