The 4,055-home Mission Village community would follow the 1,342-home Landmark Village community. Click image to enlarge.

Eight years after it was conceptually approved, a 20,660-home “mini city” west of Interstate 5 in the Santa Clarita Valley is scheduled to take two giant leaps forward next month.

On Oct. 4 the Los Angeles County Board of Supervisors is slated to consider the first phase of The Newhall Land and Farming Co.’s Newhall Ranch project – followed by a review of the second phase Oct. 25.

A total of five phases of homes and businesses comprise the Newhall Ranch. Supervisors approved its guiding document, the Newhall Ranch Specific Plan, in 2003.

The first phase is Landmark Village, a 263-acre, 1,342-home community to be located south of Highway 126 and northwest of Six Flags Magic Mountain. It would consist of 583 condominiums, 451 apartment units, 308 single-family homes and 15 commercial buildings.

The second phase is Mission Village, a 1,262-acre, 4,055-home community bounded by Westridge on the south, Magic Mountain on the east, and Highway 126 on the north and west. It would consist of 3,704 multi-family units, 351 single-family homes, 1.56 million square feet of commercial space, an elementary school, library, fire station and bus transfer station.

Phase 1 calls for the removal of 67 oak trees including 10 heritage oaks, while Phase 2 calls for the removal of 143 oaks including 8 heritage.

The acreage totals listed above do not include off-site improvements included with each phase, such as three protected spineflower habitats and 693 acres of open space with Mission Village.

Landmark Village received Regional Planning Commission approval in early 2008 but was held up when the U.S. Army Corps of Engineers raised concerns about encroachment on the Santa Clara River where endangered plants and animals live.

The biggest difference between the version approved by the Regional Planning Commission and the version supervisors will consider Tuesday is the additional setback from the river, said county Planner Samuel Dea.

Also, what was originally seen as a future highway was downgraded to a major arterial because the wider road won’t be needed to serve the development, Dea said. Other changes include the addition of a climate-change section to environmental documents to make them conform with current laws, he said.

Contrarily, when the board reviews Mission Village, it will be ruling on an appeal filed by Santa Clarita Organization for Planning and the Environment, following the Regional Planning Commission’s approval of the project in May.

The net effect, however, is the same. Both phases are up for final approval by the board.