The St. Mary's County public schools agreed Tuesday to buy a 55-acre parcel north of Lexington Park that is intended as a site for an elementary school and a middle school, said Bradley Clements, the system's chief administrative officer.

The school system plans to buy the land, in the California area at the western end of Wildewood Parkway, from developer Wildewood Residential LLC for an undisclosed price.

The school sites, which need approval from the state, are intended to provide relief in a school system that is so crowded that residential building in some areas has nearly ground to a halt to prevent adding students.

The agreement follows two other recent acquisitions by the school system. One is a 45-acre parcel on St. Andrews Church Road near the intersection with Brown Road, known as the Buchanan site, and the other is a 26-acre tract along Route 5 in Leonardtown.

Both are scheduled to have elementary schools. Clements said the school system has agreed to pay about $1.7 million for all of the properties, though he declined to break down the individual costs.

"The Board [of Education] and the superintendent have been very much focused in the California and Leonardtown areas and have really worked hard to bring these sites together," Clements said. "Right now, the key is getting the state's approval."

In addition, the school system is looking at two parcels in the California area as a potential location for a high school, Clements said.

The Wildewood school sites were initially intended to be inside the future boundaries of the Lexington Park Development District, which would have allowed the schools to hook up to the public water and sewer systems.

But the Board of County Commissioners voted in June not to change the size of the development district.

That has forced the school system to investigate other ways to supply utilities to the schools, Clements said. But that obstacle will not stop the deal.

"With the difficulty we've had in finding sites, we have to take them wherever we can get them," he said.