LYNNWOOD — A court challenge over Lynnwood’s proposed annexation has city officials wondering when — and if — voters will get a chance to decide this year whether its city limits will be expanded.

Lynnwood wants to annex about 3,690 acres of unincorporated Snohomish County north and east of the city. Mill Creek opposes the plan.

If approved, the annexation would add about 27,000 new residents to Lynnwood, boosting its population to more than 60,000 from 33,685. First, however, a majority of registered voters living within the proposed annexation boundary would have to approve it.

The Lynnwood City Council in late June settled on an April 27 special annexation election after the state Boundary Review Board for Snohomish County approved the city’s annexation proposal.

The next day, Mill Creek appealed the review board’s decision to Snohomish County Superior Court. A judge is scheduled to hear Mill Creek’s appeal at 9 a.m. Friday.

Mill Creek objects to Lynnwood’s proposal to annex land east of I-5. Mill Creek maintains in court papers the freeway is a natural boundary between the two cities even though its own city limits end about two miles east of I-5.

Lynnwood’s proposed annexation would add neighborhoods east of I-5 as far as Larch Way and south of 164th Street SW.

“Lynnwood wants everything south of 164th because that’s where Wal-Mart is,” said Bill Trimm, Mill Creek’s community development director, Tuesday. “We’re trying to develop a city long term that develops a sense of community. We felt using I-5 is a realistic western boundary for the city.”

It’s not known when the judge will issue a decision, but Lynnwood officials said it could take weeks or more.

“It’s highly improbable we’re going to be able to make the April date,” said Paul Krauss, Lynnwood’s community development director.

A Mill Creek appeal could further delay or even eliminate Lynnwood’s opportunity to schedule an annexation election in 2010.

Lynnwood stands to gain millions of dollars of the state’s share of its sales tax revenues if it annexes 10,000 or more residents into the city.

Krauss said state land use regulations that encourage cities to provide the majority of a county’s urban services — not money — is the main reason the city’s seeking the annexation.

Last month, Lake Stevens and Marysville annexed thousands of residents into their cities. Marysville’s annexation makes it the second largest Snohomish County city after Everett.

Oscar Halpert: 425-339-3429, ohalpert@heraldnet.com.