Old Man's Valley Cemetery, Heritage-listed cemetery in Hornsby, Australia.

Old Man's Valley Cemetery is a burial ground in Hornsby, New South Wales, containing graves and memorials from 1879 to 1931. The site holds approximately 25 plots marked by headstones that reflect the lives of early European settlers in the local area.

Thomas Edward II, district constable and first settler in the Hornsby area, was promised the land grant including Old Man's Valley in 1823. His descendant Thomas Edward III is believed to have established the cemetery after his youngest son Harrold died, and the earliest dated inscription is a memorial to Ann Elizabeth Harrington, who died in 1871. Burials took place from 1879 to 1931, ending with Loretta Jansson, interred under special permission during the Great Depression.

The name Old Man's Valley is thought to have been given by Thomas Edward Higgins II, who took up the land grant; the valley was a woman's site in Aboriginal tradition, guarded by the Gurang, the old Kangaroo people, with a freshwater spring at the foot of what is now a quarry. Family members recall that the midwife Ann Harrington buried stillborn and other infants in unmarked graves near the east boundary.

The cemetery is accessible via Quarry Road in Hornsby and offers visitors a quiet setting to explore the gravestones. Interpretative signs at the location explain the history of the burial ground and the Higgins family.

The earliest dated inscription is a memorial to Ann Elizabeth Harrington, who died in 1871 aged 14 months; she was buried in the family orchards, not in the cemetery. Family members also recall that midwife Ann Harrington buried stillborn and infant babies in unmarked graves near the east boundary.