Hertfordshire on Wikipedia.
 

Abbots Langley.
Albury, St. Mary the Virgin. © Bill McKenzie.
Aldbury, St. John the Baptist. SP 963 125. © Les Needham.
Anstey, St. George. From an old postcard in Reg Dosell's Collection. Link.
Ardeley, St. Lawrence. TL 318 272. © Les Needham.
Ashwell, St. Mary the Virgin. © Bill McKenzie. An old postcard view, from Reg Dosell's Collection. U.R.C. TL 268 397. © Les Needham.
Aspenden, St. Mary. TL 353 284. © Les Needham. Link.
Ayot St. Lawrence, St. Lawrence Old Church. © Bill McKenzie.
Ayot St. Peter, St. Peter. © Bill McKenzie.

Babbs Green, former church. © Bill McKenzie.
Baldock.
Bayford, St. Mary. © Bill McKenzie.
Bedmond, Church of the Ascension. © Les Needham. Link.
Berkhamsted.
Bishop's Stortford (Hockerill), dedicated to All Saints. © Robert Mather. 167 TL 494 214. St. Michael. From an old postcard in Geoff Watts' Collection. Interior view, from an old postcard in Steve Bulman's Collection. Link.
Bovingdon, St. Lawrence. © Derek Collier. Link.
Bramfield, St. Andrew. TL 328 125. © Thomas Curtis. Link.
Brent Pelham, St. Mary the Virgin. TL 433 308. © Graeme Wall. Link.
Broxbourne, St. Augustine. From an old postcard (franked 1921?), Bulman Collection.
Buntingford, the shell of St. Bartholomew at Layston, which was the original parish church. The cemetery remains in use. TL 369 301. St. Peter is the present parish church. TL 363 293. Link. St. Richard (R.C.). TL 363 292. U.R.C. TL 361 294. All © Les Needham.
Bushey, St. James. From an old postcard, Steve Bulman's Collection.
Bushey Heath, St. Peter. Link to external site.

Chipperfield, St. Paul. TL 043 015. Link. Baptist Church. TL 041 018. Both © Chalmers Cursley.
Chorleywood.
Codicote, St. Giles. TL 219 188. © Thomas Curtis. Link.
Cottered, St. John the Baptist. TL 318 292. © Les Needham. Link.
Croxley Green.

Datchworth, St. Andrew. © Bill McKenzie.

Flamstead End, St. Leonard. © Bill McKenzie.
Flaunden, St. Mary Magdalene. TL 013 008. © Chalmers Cursley. The old church was demolished in 1843/4. From an old engraving in Colin Waters' Collection. Former chapel, now a private house. TL 016 010. © Chalmers Cursley.
Furneux Pelham, St. Mary the Virgin. TL 430 280. © Graeme Wall. Link.

Great Amwell, St. John the Baptist. © Bill McKenzie. An old postcard view (card franked 1909), from Reg Dosell's Collection. Link.
Great Gaddesden, St. John the Baptist. © Bill McKenzie. Another view. © Derek Collier.
Great Wymondley, St. Mary. TL 215 285. © Thomas Curtis. Link.

Hadham Cross, Congregational Church. TL 427 186. © Chalmers Cursley. Another view. © Bill McKenzie.
Hatfield, St. Etheldreda. Another view. TL 235 085. Both © Thomas Curtis. Link.
Hemel Hempstead.
Hertford.
Hertingfordbury, St. Mary. © Bill McKenzie.
Hexton, St. Faith. Another view. Both © Bill McKenzie.
Hinxworth, St. Nicholas. © Bill McKenzie.
Hunsdon, St. Dunstan. TL 418 127. © Chalmers Cursley. Link.
Hoddesdon, St. Augustine (R.C., 1962). From Fr. Philip Miller's Collection. Link.

Ickleford, St. Kathryn. © Bill McKenzie.

Kelshall, St. Faith. © Alan Craxford. An old postcard view from Reg Dosell's Collection. Link.
Kensworth, St. Mary the Virgin. © Bill McKenzie.
Kimpton, St. Peter & St. Paul. © Bill McKenzie.
Kings Langley.
King's Walden, St. Mary. © Bill McKenzie. Link.
Knebworth, St. Martin. © Bill McKenzie. St. Mary, at Knebworth House. TL 231 210. © Thomas Curtis. Link.

Langleybury, St. Paul. TL 080 006. © Les Needham. Link.
Lemsford, St. John the Evangelist. © Bill McKenzie. An old postcard view, from in Reg Dosell's Collection. Link.
Letchworth.
Leverstock Green, Holy Trinity. TL 085 065. © Les Needham. Link.
Lilley, St. Peter. © Bill McKenzie.
Little Amwell, Holy Trinity. © Bill McKenzie.
Little Berkhampstead, St. Andrew. © Bill McKenzie.
Little Gaddesden, St. Peter and St. Paul. © Bill McKenzie.
Little Hadham, St. Cecilia. © Bill McKenzie.
Long Marston, All Saints. SP 895 158. © Bill McKenzie. Another view.  The church dates from the 1880's, and was built to replace a medieval chapel of ease, of which only the 15th century tower survives. SP 894 156. Both © Les Needham. The former Baptist Chapel, now in residential use, dates from 1863. SP 898 155. © Les Needham. Former Wesleyan Chapel (1864), now also a private residence. SP 898 157. © Les Needham.

Markyate, St. John the Baptist. © Bill McKenzie.
Monken Hadley, St. Mary the Virgin. © Bill McKenzie.
Much Hadham, St. Andrews Holy Cross (Congregational and R.C.). TL 430 196. © Bill McKenzie. Another view. © Chalmers Cursley. Link (R.C.).

Nettleden, Church of St. Lawrence. © Bill McKenzie.
Newgate Street, St. Mary Ponsbourne. © Bill McKenzie.
North Mymms, St. Mary. © Eddie Murray. Link.
Northaw, dedicated to St. John the Evangelist. © Bill McKenzie. An old postcard view, from Reg Dosell's Collection.
Northchurch, St. Mary. SP 974 088. Baptist Church. SP 975 086. Link. Both © Les Needham.

Pirton, St. Mary the Virgin. © Bill McKenzie. Despite being labelled as St. Mary Magdalene, Great Offley, this old postcard in Reg Dosell's collection is clearly Pirton. Thanks to Janet Gimber for unravelling this little mystery. Link.
Potten End, Holy Trinity. TL 017 089. © Les Needham.
Puttenham, St. Mary. SP 885 149. © Les Needham. Link.

Rickmansworth.
Ridge, St. Margaret. TL 214 005. © Thomas Curtis. Link.
Royston, St. John the Baptist. Interior view. Both © Alan Craxford. Link.
Rushden, St. Mary. From an old postcard in Reg Dosell's Collection.

St. Albans.
St. Ippolitts, St. Ippolitts. The tower. TL 198 272. Both © Bill McKenzie. Another view. © Thomas Curtis. Link.
St. Paul's Walden, dedicated to All Saints. © Bill McKenzie.
Sandridge, St. Leonard. TL 172 106. © Thomas Curtis. Link.
Sarratt, Church of the Holy Cross. TQ 038 984. © Derek Collier. Link.
Stansted Abbotts, St. Andrew. © Bill McKenzie. An old postcard view, from Reg Dosell's Collection.
Stapleford, St. Mary. From an old postcard in Reg Dosell's Collection. Link.
Stevenage, St. Nicholas. TL 241 262. © Thomas Curtis. An old postcard view, from Reg Dosell's Collection. Link.
Stocking Pelham, St. Mary. TL 447 293. © Graeme Wall.

Tewin, St. Peter. TL 268 143. © Thomas Curtis. Link.
Therfield, St. Mary the Virgin. Link. Baptist Church. Both © Alan Craxford.
Throcking, Holy Trinity. TL 339 302. © Les Needham. Link.
Tring.

Walkern, St. Mary the Virgin. TL 302 266. Link. U.R.C. TL 301 265. Both © Les Needham.
Warners End, St. Alban. TL 041 075. © Les Needham.
Waterford, St. Michael & All Angels. © Bill McKenzie.
Watford.
Watton-at-Stone, St. Mary & St. Andrew. © Bill McKenzie.
Welwyn, St. Mary the Virgin. © Bill McKenzie.
Wheathampstead, St. Helen. © Bill McKenzie.
Widford, St. John the Baptist. TL 413 158. © Bill McKenzie. Another view. © Chalmers Cursley. And an old postcard view, from Reg Dosell's Collection.
Wigginton, St. Bartholomew. SP 940 103. Link. Baptist Chapel. SP 939 101. Both © Les Needham.
Willian, All Saints. Another view. Both © Christopher Skottowe. Link.
Wilstone, St. Cross. SP 904 140. © Les Needham. Link.
Wyddial, St. Giles. © Tim Tomlinson.