Cityline Partners’ proposed redevelopment of 19 acres on Westpark Drive in Tysons Corner, as seen from the south.

Westpark Office Park is the subject of the most recent — and possibly final — major application for zoning changes and colossal development plans in Tysons Corner.

Cityline Partners, the development group that controls Tysons Corner’s largest portfolio of properties, submitted plans to Fairfax County last week to transform the seven-building 1970s-era office park along Westpark Drive into up to 2.4 million square feet of new development. It is the 12thapplication county officials have received and, with the area’s major landowners and developers mostly accounted for, may be the last of the large, mixed-use plans for the near future.

This is the second submission for Cityline, the development manager for DLJ Real Estate Capital Partners, following its proposal to remake the Westgate Office Park in February. Cityline’s Thomas Fleury said despite the uncertainties that still linger in Tysons regarding transportation, street grids and other infrastructure, it was important to float plans early into those conversations.

“At some point you say you make that investment,” he said.

The Westpark office buildings, all built against a hillside between 1970 and 1975, occupy 19 acres north of Chain Bridge Road between Tysons Galleria and the Capital Beltway, about one-third of a mile from the Tysons Central 123 Metrorail station that is currently under construction and set to open in 2013.

The centerpiece of the Westpark plans is an urban park accentuated by a fountain made to look like a wall of water, an illuminated glass elevator pavilion and a staircase connecting with a plaza below. Around it the company plans six urban blocks with three alternative development plans, ranging from 1.8 million to 2.4 million square feet.

There could be as many as eight new buildings, two more than compose the CityCenter project that Hines and Archstone began building last month in downtown Washington. Cityline proposes a 283-unit, six-story residential building, a 402-unit, 18-story residential building, three office buildings totaling at least 879,000 square feet and a full-service 10-story hotel.

An office-focused version of the plans would include two more office buildings, while a housing-heavy version would include another two residential towers, both 17 stories high and featuring 240 units apiece.