The county Park Authority is beginning what officials called the "largest planning process" in the agency's history to decide how to use more than 4,000 acres of parkland in the Cub Run and Bull Run watersheds in western Fairfax.

The first in a series of meetings to get public comments is scheduled for 7 p.m. June 23 at Westfield High School in Chantilly. Next month, three more meetings are scheduled, each to focus on specific topics such as recreation, natural and cultural resources, and trail connections and access, according to Angie Allen, the project manager.

"This is a really big deal. It is a lot of land that we are covering, and it is a really broad and comprehensive approach we are going to take planning these new parcels and making links to current parcels," Allen said.

As part of the Sully Woodlands regional master plan, park officials are looking for feedback on how to use or preserve about 2,250 acres of existing parkland and about 2,150 acres acquired by the authority in the past five years. The land is in watershed areas, and most of it is going to be preserved instead of developed. The existing parkland includes E.C. Lawrence Park, Cub Run Stream Valley and Richard W. Jones Park.

"At this point," said Judy Pedersen, spokeswoman for the authority, "based on what we know, 90 percent-plus of the land is going to remain pristine."

The authority is using the meetings to find out what the public feels the community's needs are, whether more soccer fields, baseball diamonds or walking trails. "What we are trying to do is create a resource-driven plan," Allen said, "where we look at what is special out there in the form of cultural and natural resources and then decide what areas are appropriate for development. So it is important to get people out to these meetings and get their input."

Allen said this project differs from other authority plans in that it is not a single site. The land covers many parcels that the authority hopes to assemble.

"Typically," Allen said, "we tend to plan individual park sites. Here we are looking at this huge assemblage of parks and how we can make it work as a system. Here we are looking at new and existing parks, and it is really a broad-based study. It is going to be different."

What won't be different about this project compared with a single site are challenges related to this area's history.

"We have a lot of significant cultural resources out there," Allen said. "There is a high likelihood of archaeological resources dating from Native American times through the Civil War."

She said the area comprises a variety of land types.

"The property ranges from very rare forest type to old sod farms," Allen said. The mix of cultural and natural resources "is the balance we face at every single park. And here it is a good thing, because instead of looking at one individual property, we are looking at a large assemblage. That gives us a little more room to see what works, what makes sense and what is the best balance."

Westfield High School is at 4700 Stonecroft Blvd. For more information, call 703-324-8662.