Missing only one major link, the long-envisioned Bay-to-Ridge Trail is nearly complete.

On the latest version of the city's Palo Alto Open Space map, the 16-mile trail appears as a long orange line, curving southwest from the Palo Alto Baylands' sailing station through Monte Bello Open Space Preserve in the foothills. Just off the map, the trail extends to the Skyline Ridge Open Space Preserve.

On the ground, it is largely unmarked, passing invisibly through places Palo Alto pedestrians already tread — North California Avenue, Stanford Avenue, Old Page Mill Road, the Pearson-Arastradero Preserve and Foothills Park.

In the minds of its supporters, the Bay-to-Ridge Trail represents something even larger. It links the Palo Alto of daily life with the Bay's waters and the west's wooded hills, unimpeded by city boundaries, property ownership or freeways — or by residents-only rules.

It connects the San Francisco Bay Trail and the Ridge Trail, two major efforts to construct Bay-ringing hiking paths.

And someday, that path will continue all the way to the Pacific Ocean.

"It's just very cool to ... walk out of your door and up to the top of Skyline and down to the ocean," Councilwoman Yoriko Kishimoto said. "It's really a beautiful vision."

As mayor last year, Kishimoto presided over a significant milestone for the trail, the completion of links between Los Trancos Open Space Preserve and Foothills Park and between Foothills Park and the Arastradero Preserve. She and Palo Altan Nonette Hanko, a founder and longtime board member of the Midpeninsula Regional Open Space District (MROSD), jointly hammered in a 3-foot-long wooden "spike" painted gold at the place the trail through the city's Foothills Park connects with MROSD lands.

Previously, Foothills Park trails didn't connect with anything, on purpose, to protect its status as accessible only to Palo Alto residents.

But in 2005, the City Council had to agree to open Foothills to through hikers to secure $2 million from the California Coastal Conservancy and Santa Clara County to purchase 13-acre Bressler property, which was subsumed into the Arastradero Preserve.

By co-opting a utility road and constructing a new trail, those links were completed in September 2007.

"That's really the lynchpin that created the Bay-to-Ridge," Greg Betts, the city's acting community-services director, said of the connection.

Betts entered the nearly complete trail into a statewide contest this spring. It won, capturing a trail-project merit award at the California State Parks' California Trails and Greenways Conference in May.

"The trail not only links parks and open-space areas with urban neighborhoods as the trail passes from tidal marshlands to redwood forests, there are four nature interpretive centers along the trail route to allow travelers to learn about the ecology of the different plant communities along the way," Betts wrote in the award application.

The history of the trail dates back more than a third of a century. It was conceived by Hanko when she was envisioning creation of the MROSD in 1972, as a spinoff of an earlier trail vision: a trail all around the Bay, envisioned by Mary Gordon, then a member of the Palo Alto Planning Commission.

Frances Brenner, also a commission member, favored the city acquiring the former Arastra Ltd. property. In the mid-1960s, a development firm proposed building 1,776 houses on the land, but the city denied it, rezoned the property and in the mid-1970s was forced to acquire the land in a court decision, for a negotiated price of $7.5 million. The land is now a key link in the Bay-to-Ridge Trail.

Hanko, who still serves on the MROSD board, said the Bay-to-Ridge Trail has been a campaign position every time she faces re-election — although she hasn't had to campaign in recent elections because no one has run against her.

Former MROSD Planner Del Woods actually developed a trail alignment along the periphery of Foothills Park, but it was steep and close to private properties.

Betts, as director of open space and parks, suggested looking at existing trails, and Craig Beckman of the MROSD suggested that the best alignment would be to link to the district's Los Trancos Preserve, near the top of Page Mill Road.

Former Palo Alto City Council members and mayors Judy Kleinberg and Dena Mossar also supported the trail concept.

A county planner, Lisa Killough, was put in charge of trails countywide and was one more catalyst in moving the trail forward, Hanko recalled.

Along the way, the Bay-to-Ridge trail was included in the 1995 Santa Clara County Trails Master Plan.

Trail planning kicked off in earnest following the adoption of Palo Alto's 1998 Comprehensive Plan, which called for the city to "evaluate the design of a Bay-to-Foothills path."

Practicality largely drove the selection of the route, Betts said.

"In one sense, the route is the shortest distance between two spots," he said.

Planners utilized an existing path over U.S. Highway 101 and the California Avenue underpass below the railroad tracks. They tried to connect parks and green space — the trail touches Jordan Middle School, Alexander Peers Park, Jerry Bowden Park and comes close to Donaldina M Cameron Park.

And planners used the four nature centers — Lucy Evans Baylands Nature Interpretive Center, the Junior Museum and Zoo, the straw-bale gateway facility at Pearson-Arastradero and the Daniels Nature Center in the Skyline Ridge Open Space Preserve — as anchors, Betts said.

They also used existing trails.

In the built-out areas of Palo Alto, planners aimed for less-busy roadways and wide sidewalks, Betts added.

"Palo Alto itself is still a really beautiful route," he said.

One gap remains in the trail. Between Old Page Mill Road and the Arastradero Preserve, across Interstate 280, the path needs to cross Stanford University land.

Stanford agreed to build the critical link as part of its 2000 General Use permit, in which it agreed to construct two trails.

Known as S-1, or southern trail, the Bay-to-Ridge connector was approved — but is now tied up in the lawsuit challenging the northern Stanford trail proposal along Alpine Road.

"Sometimes it just takes longer to build a trail than it does to build a roadway," Betts said. "Sometimes it just takes a while for pieces to fall into place as it did with the serendipity of the 13-acre Bressler property."

Betts said he only knows of one person who has hiked the length of the trail, although others including Kishimoto have hiked large chunks of it.

"We acknowledge that it's not going to be an ant trail of people," he said.

Anyone eager to hike the trail should prepare carefully. It is long and, as its name suggests, climbs more than 1,400 feet. Most of the trail is unmarked so a map is essential for first-time trail hikers.

Signs through the Pearson-Arastradero Preserve, for example, still state trails end at Foothills Park and once at the boundary, a hiker arrives perpendicular to a road, with no clear indication which way to go.

Click here for the Bay-to-Ridge Trail map.