The North Coast's two congressional districts were dramatically altered in maps approved Friday by the California Citizens Redistricting Commission, putting Santa Rosa, Rohnert Park and Cotati in an inland district that includes Democratic Rep. Mike Thompson's hometown of St. Helena.

Most of the rest of Sonoma County is in a coastal district stretching from the Golden Gate Bridge to the Oregon border, obliterating the compact Sonoma-Marin district held by retiring Rep. Lynn Woolsey, D-Petaluma.

Thompson's base in Napa County is cut off from the North Coast, which he has represented in Congress since 1999 and for eight years before that in the state Senate.

The 14-member commission intends to certify the maps without changes Aug. 15.

"We have created a new landscape," Chairwoman Connie Galambos Malloy said. The new districts were drawn without regard to voter registration patterns or candidates' addresses, she said.

Under the new state Senate map, Santa Rosa is in a coastal district that stretches from Marin County to the Oregon border, but Petaluma, Rohnert Park and Cotati are at the west edge of a district that spans the Interstate-80 corridor from Vallejo to Davis.

The Assembly map puts Democrats Wes Chesbro of Arcata and Michael Allen of Santa Rosa in the same district.

Santa Rosa is sliced in half by an east-west line running largely along College Avenue, with the northern portion in a coastal Assembly district extending to the Oregon border and the southern portion of the city in a compact district with Petaluma and Marin County.

Chesbro, a former state senator, and Allen, a freshman lawmaker, both declined to discuss their geographic conflict.

Allen said he would meet with Chesbro and talk to his own advisors. "I think we're all scratching our heads and looking at this," he said.

Chesbro said only that he was pleased to see the North Coast remain in one Assembly district.

The new districts would apply to the 2012 primary election, barring lawsuits that put the final decision before the courts.

Thompson, a seven-term incumbent, has not said what congressional district he will run in next year. He is withholding comment on the new maps "until the process is finalized," an aide said Friday.

Three Marin-based Democratic candidates — Assemblyman Jared Huffman, Norman Solomon and county Supervisor Susan Adams — are vying to replace Woolsey in the coastal congressional district.

Regarding the new state Senate configuration, Petaluma City Councilman Mike Healy said that his city has "little in common" with Sacramento Valley cities like Fairfield and Vacaville and would not be "effectively represented" by the new district's senator.

Brian Sobel, a former Petaluma councilman, acknowledged that the city may feel more kinship with the North Bay, but that consideration may have been sidelined by the commissioners.

"It really comes down to a numbers game," Sobel said, referring to the legal requirement that districts be of similar population.

The commission voted 13-1 to approve the state Senate, Assembly and Board of Equalization final draft maps, with the lone nay vote cast by Commissioner Michael Ward, a Republican from Anaheim.

Ward said the commission had "failed to strictly apply constitutional criteria" in drawing the maps.

The proposed maps for California's 53 congressional districts were approved on a 12-2 vote. Ward and Commissioner Jodie Filkins Webber, a Riverside County Republican, opposed the final draft maps.

Appointed in November, the commission consists of five Democrats, five Republicans and four members from neither of the two major parties.

Commissioner Angelo Ancheta, a law professor at Santa Clara University and a Democrat, called the open redistricting process "an experiment in democracy" and said it was impossible to draw perfect boundaries.

"I am fully prepared to defend these maps in court," Ancheta said.

Political districts are reshaped every 10 years after the census to adjust for population shifts, ensuring each district has the same number of voters. In the past, the lines were redrawn by the Legislature.

-- Guy Kovner, The Press Democrat