Updated

Historical activists have reached an agreement to save a portion of a Revolutionary War battlefield in New Jersey from development.

The Civil War Trust tells The Associated Press on Monday that it will pay an academic institute $4 million for nearly 15 acres across from Princeton Battlefield State Park. It still needs to raise most of the money.

The Maxwell's Field site is where historians believe George Washington's charge first struck British lines during the Battle of Princeton in January 1777. The land will be donated to the state to become part of the park.

The Institute for Advanced Study is building faculty housing on part of the land it is keeping.

The deal also hinges on approval from two local commissions.