Hertfordshire sits immediately north of London — a county shaped by the Roman road network, the Victorian railway that opened it to the capital's commuters and the institutional heritage of a county that housed London's overflow hospitals, asylums and schools in its rural estates. Its abandoned places range from a Victorian psychiatric hospital campus in the Colney valley to a Roman bathhouse sealed beneath a motorway and the country house estates of the Hertfordshire gentry. Here are 5 of the best abandoned places in Hertfordshire, selected from our Abandoned Places Map UK — 640+ GPS locations across England, Scotland, Wales and Ireland.
Why Hertfordshire Is a Hidden Gem for Urban Exploration
Hertfordshire's proximity to London made it the natural recipient of the Victorian metropolitan overflow — asylums, hospitals, schools and sanatoria were built across the county to house populations that London couldn't contain. Combined with the county's Roman and medieval heritage and the country house estates of the Hertfordshire gentry, the result is a surprisingly varied urbex landscape that most explorers miss entirely on their way to or from the capital.
1. Napsbury Hospital – London Colney, Hertfordshire — 1905 London County Asylum, Complete Kirkbride Campus, Gothic Water Tower, Atmospheric Dereliction (Known Location)
Napsbury Hospital in London Colney opened in 1905 as the London County Council's Asylum No. 10 — a complete Kirkbride-plan psychiatric campus built to serve London's growing psychiatric population on the Hertfordshire rural estate. The Gothic water tower, the ornate chapel, the ward buildings and the administrative block still stand in various states of atmospheric decay. Parts of the campus have been converted to housing but significant original structures remain derelict. One of the most architecturally complete and most atmospherically powerful abandoned asylum campuses within easy reach of London.
🔗 Learn more: Wikipedia – Napsbury Hospital
2. RAF Hunsdon – Hunsdon, Hertfordshire — 1941 WWII Mosquito Base, Control Tower and Dispersal Pans Still Standing, Rural Hertfordshire Farmland (Known Location)
RAF Hunsdon near Ware was established in 1941 as a night intruder and bomber support station — home to de Havilland Mosquito squadrons that flew low-level precision strikes against targets across occupied Europe. Closed after WWII and returned to agriculture, the original control tower still stands above the surrounding Hertfordshire farmland with dispersal hardstandings and blast pens still traceable across the site. One of the most completely surviving and most historically specific small WWII airfield sites in the Home Counties — a Mosquito base within easy reach of London.
🔗 Also read: Top 5 Abandoned Places in England →
3. Munden House – Watford Rural, Hertfordshire — Grade II Listed Georgian Country House, Long-Term Derelict, Stable Block and Walled Garden, Hertfordshire Green Belt (Known Location)
Munden House is a Grade II listed Georgian country house in the Hertfordshire green belt — a substantial late 18th-century mansion that has been in progressive dereliction for an extended period, listed by Historic England as a heritage at-risk property. The Georgian architecture, the overgrown grounds, the stable block and the walled garden make it one of the most discussed abandoned country houses in Hertfordshire. Documented by British Listed Buildings and consistently referenced by Hertfordshire heritage campaigners as a building that deserves better than its current condition.
🔗 Learn more: British Listed Buildings – Munden House
4. Hertfordshire WWII Decoy Town – 1940s Starfish Bombing Decoy, Concrete Fire Baskets and Control Bunker Still Traceable, Rural Hertfordshire (Our Map Exclusive)
A 1940s Starfish bombing decoy site in rural Hertfordshire — the original concrete fire basket emplacements still visible in the field, the control bunker from which the decoy fires were lit during German bombing raids and the perimeter access track still traceable through the farmland. Starfish sites were built near major industrial and urban targets to draw German bombers away from cities; the Hertfordshire sites protected London's northern suburbs. GPS coordinates available with our England Urbex Map.
5. Victorian Hertfordshire Sanatorium – 1890s-1900s Tuberculosis Pavilion Wards, Original Verandah Sleeping Galleries Still Intact, Woodland Setting (Hidden Gem — Our Map Only)
An 1890s-1900s tuberculosis sanatorium in the Hertfordshire countryside — the original pavilion ward buildings with their characteristic verandah sleeping galleries where patients slept in the open air to receive fresh air treatment, still standing in the surrounding woodland. Hertfordshire's dry climate and proximity to London made it a favoured location for tuberculosis institutions; several sanatorium campuses were built across the county between 1890 and 1920. Included in our England collection — 400+ locations.
Safety Tips
- Asbestos: endemic in pre-1980 Hertfordshire institutional buildings — FFP2 mask mandatory in any enclosed space at Napsbury or sanatorium sites
- Roman sites: the Welwyn Roman Baths require advance booking through the Welwyn Hatfield Borough Council — never attempt to access the vault independently
- Never explore alone — always bring at least one other person
The urbex code: "Leave it as you found it — the next explorer deserves the same experience."
❓ FAQ
What is the most famous abandoned place in Hertfordshire?
Napsbury Hospital in London Colney — a 1905 London County Council asylum campus whose Gothic water tower, ornate chapel and ward buildings represent one of the most architecturally complete Victorian psychiatric campuses within easy reach of London.
What was RAF Hunsdon?
A 1941 WWII night intruder station in Hertfordshire — home to de Havilland Mosquito squadrons flying precision strikes over occupied Europe. Closed after WWII and returned to farmland; the control tower and dispersal infrastructure are still traceable in the Hertfordshire countryside.
What were Starfish bombing decoy sites?
WWII deception installations built near major urban and industrial targets — networks of electrically controlled fire baskets that were ignited during German bombing raids to simulate a burning city and draw bombs away from their intended targets. Over 200 Starfish sites were built across Britain between 1940 and 1944.
🎯 Summary
Hertfordshire's abandoned places range from a 1905 London County asylum with a Gothic water tower to a 3rd-century Roman bathhouse sealed in a steel vault beneath the M1 and a WWII bombing decoy site in a field. Each of these 5 derelict buildings in Hertfordshire reveals the hidden layers beneath England's most overlooked commuter county.
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