Carlheim (also called Paxton) is a mansion located in the northeast part of Leesburg, Virginia. It was constructed in about 1872 for Pennsylvania industrialist Charles R. Paxton (1816–1889) and his wife Rachel who continued to live there until her death in December 1921. When constructed, it sat on over 760 acres (3.1 km2) roughly bounded on the north end by the Red Rock Wilderness Overlook Regional Park, the Balls Bluff Battlefield and the Potomac River. In accordance with Mrs. Paxton's will, the buildings and 50 surrounding acres were preserved and organized into a charitable trust to benefit "needy children."
Designed by New York architect Henry Dudley, the nearly 20,000-square-foot (1,900 m2) 32-room Second Empire building was listed on the National Register of Historic Places in 1979 for its architectural and local significance. In 2004, the property became a non-contiguous part of the Leesburg Historic District. The estate of Mr. and Mrs. Paxton was originally entered down a long tree lined driveway off of King Street. Today, that entrance is gone and there are two more contemporary entrances; Wildman Street (normally closed) and the new main entrance that was completed in 2009 at 601 Catoctin Circle.
Among the buildings that remain from the original estate but are outside the present campus include the Farm Managers Home (now the Exeter Community Club House) and the stabilized creamery ruins at Red Rock Park along Edwards Ferry Road.
The mansion and remaining 16-acre (65,000 m2) grounds are currently the home of the Margaret Paxton Memorial Learning and Resource Campus (also known as the Paxton Campus) which includes The Arc of Loudoun, The Aurora School, the ALLY Advocacy Center, Open Door Learning Center and STEP Up program. The Aurora School serves children and young adults with intellectual and developmental disabilities. Open Door is an inclusive preschool serving children ages 2–7 years with and without disabilities. The ALLY Advocacy Center provides advocacy services and social opportunities for people of all ages and abilities. The Paxton Campus is a registered non-profit organization registered under its legal name, The Arc of Loudoun. The Campus is privately owned property but holds several events open to the general public.
The major annual fundraising events on the Paxton Campus include:The Music at the Manor free concert series (May)
The Paxton Manor Haunted House aka "Shocktober" (October)