The park preserves the cultural and natural resources of western Fairfax County and has a long and complex history lasting 8,000 years.

Approximately four miles of mostly earthen trails are accessible from the Visitor Center, the pond, Cabell's Mill and the park's northern terminus on Poplar Tree Road.

The trails pass through the park's diverse habitats and are popular with birders, runners, dog walkers, and families.

Through the lease, Brown was required to have a 200-tree apple orchard and pay an annual rent of 530 pounds of dried and cured tobacco.

By 1776, Thomas Brown and his youngest son Coleman had acquired some 630 acres, sold the “three-lives lease” and may have built the stone house that would become Walney Visitor Center.

Coleman left the bulk of the farm to the children of his daughter, Mary Lewis, with the expectation that it would be sold and the proceeds divided among them.

Whoever was responsible, the farm was in poor condition in 1843 when, following Elizabeth's death, it was sold to Lewis H. Machen, one of Thomas Brown's great-grandchildren.

[5] In 1843 Lewis H. Machen purchased 725 acres from Coleman Brown's grandchildren for $10,879 and moved to the property with his wife Caroline, daughter Emmeline, and sons Arthur and James.

Lewis Machen had a large and valuable collection of books and he converted the small stone house into a library and study.

A participant of the scientific farming movement of the 1840s and 1850s, Lewis experimented with crop rotation and the use of fertilizer including Peruvian guano.

[8] The eldest son, Arthur, lived at Walney in his teen years, operating the farm alongside his brother James.

To help them manage the farm, the Machens hired white farmhands and rented enslaved African Americans from slave-owners.

Walney witnessed extensive troop movement during the American Civil War due to its proximity to Washington, D.C.

In the winter of 1861-1862, over 40,000 troops camped in the Centreville area, cutting down local trees for firewood, fortifications and shelter, damaging woods, fields, and gardens.

Caroline and daughter Emmeline would remain in Baltimore for the rest of their lives, returning to Walney only for family visits.

While historians do not know for certain why James did this, contributing factors could be the death of his wife Georgie in 1895, or the fact that none of his children were interested in taking over the farm.

Though the property would become part of their country estate and retreat from Washington, D.C., the Lawrences rented the Walney stone house to various tenants and never lived there.

When Ellanor C. Lawrence died in 1969, she willed the property to her husband with the intent that it be given to a public agency so that its natural and cultural resources could be preserved.

In 1971, David Lawrence deeded 640 acres including Walney and Cabell’s Mill to the Fairfax County Park Authority in memory of Ellanor.

1727 Francis Awbrey granted land south of Rocky Run unknown John Tayloe purchases from Francis Awbrey 1740 Willoughby Newton purchases from John Tayloe 1742 Thomas Brown leases 150 acres from Willoughby Newton 1767 Katherine and John Lane inherit 350 acres from Willoughby Newton 1769 James Hardage Lane purchases from Katherine and John Lane 1776 Thomas Brown assigns lease to William Fintch 1776 William Fintch assigns lease to James Hardage Lane 1810 Coleman Brown purchases approx.