| Abattoir | X | X | ST6879 : Entrance to the abattoir and Westerleigh Railhead | |
| Abbey | X | X | TQ3079 : Westminster Abbey, London | Here with Abbey/cathedral symbol on 25K, World Heritage symbol on 50K |
| Abbey Grounds | X | | SP0202 : No dogs in parts | |
| Academy | X | | NY3584 : Langholm Academy | |
| Activity Centre | X | X | SD9036 : Coldwell Activity Centre | |
| Adventure Activities | X | | SD7912 : Burrs Activity Centre | Tourist site |
| Agricultural Centre | X | X | NJ7718 : Thainstone Agricultural Centre | |
| Agricultural College | X | X | TL6707 : Writtle Agricultural College, Essex | |
| Air Shaft | | X | TR3243 : Ventilation shaft near Guston | |
| Air terminal | X | X | NF6905 : Barra Airport Terminal Building | By the beach airfield on Barra |
| Airfield (disused) | X | X | NJ2665 : RAF Milltown | With name on 25K |
| Airfield | | X | NO4998 : Gliding Competition at Aboyne Airfield | |
| Airfield | X | | TG2339 : Northrepps Airfield | Airstrip on 50K |
| Airport | X | X | SV9110 : St Mary's Airport | |
| Airshaft | X | | SK3380 : Bradway Tunnel Air Shaft | |
| Airstrip | X | X | TQ1761 : Air strip, Rushett Farm | Air Strip on 25K |
| Aisled House | X | X | NF7320 : Aisled House | Non-Roman |
| Almshouses | X | X | TL9863 : Almshouses | Non-Roman |
| AMPHITHEATRE | X | X | ST3390 : Roman Amphitheatre, Caerleon | Tourist site, Roman |
| Aquarium | X | X | SZ0890 : Bournemouth Oceanarium | Tourist feature |
| Aqueduct | X | X | SY0783 : Aqueduct, East Budleigh | Also see NN7358 : Footbridge over Tummel Bridge aqueduct where on 50K the word Aqueduct is in blue letters |
| Animal sanctuary | X | | at SU933078 | |
| Arboretum | | X | SC2781 : The Arboretum at St.John's | Tourist site |
| Area of Shake Holes | X | | SD9970 : Line of shake holes | There are other 'Area of' entries |
| Arts centre | X | | HY2509 : Pier Arts Centre, Stromness | Tourist site |
| Ash | X | | SU4575 : Towards "Ash" | A single tree on a parish boundary |
| Assault Course | | X | at TL810851 | "Go Ape" Thetford Forest |
| Astronomy Centre | X | | NX4039 : Craiglemine Cottage | Craiglemine Cottage |
| Avalanche Shelter | X | X | NG9137 : The avalanche shelters on Lochcarron to Kyle of Lochalsh road | | |
| Barn | X | X | ST5038 : Fourteenth-century Abbey barn at the Somerset Rural Life Museum. | Non-Roman |
| Barracks | X | X | NT2269 : Construction Works, Redford Barracks | With name on 25K |
| Barrier | | X | TQ5477 : River Darent Flood Barrier | | |
| Bastle | X | X | NY7790 : Black Middens Bastle House | They occur in counties near the Scottish border. |
| Bath House | X | X | NS5472 : Remains of Roman Bath House, Bearsden | Tourist site |
| Baths | X | | at SP458772 | (Remains of) |
| Battery | X | X | NJ9605 : Torry Point Battery | Tourist site |
| Beacon | X | X | SY7881 : Old Navigation Beacon Chaldon Down | Beacons on 50K |
| Beam Engines | X | | SU2662 : Crofton - Pump House | Tourist site |
| Beech | X | | at SP233677 | On a parish boundary. Oaks are marked nearby |
| Beehive Hut | X | X | SX6381 : Beehive hut | Non-Roman |
| Bield | X | | NY1220 : Ruined Bield | N England & Scotland word for sheepfold |
| Bird Observatory | X | X | SY6868 : Portland Bird Observatory | |
| Bird of Prey Centre | X | X | NM7234 : Achnacroish | Tourist site |
| Bird Sanctuary | X | | SP8740 : Willen Lake in Milton Keynes | |
| Bishop's Palace | X | | ST1578 : Ruins of Bishop's Palace. Llandaff, Cardiff | Non-Roman. Old Bishop's Palace. |
| Blockhouse | X | X | SV8915 : Blockhouse on Tresco | Non-Roman |
| Blockship | X | X | ND4899 : Blockship on Number 2 Churchill Barrier | |
| Blowing House | X | | SX6363 : Blowing house | Non-Roman |
| Boarded Groin | X | X | at TR340635 | Non-Roman |
| Boat Hire and Trips | X | | NM9248 : Linnhe Marine pontoon, Dallens Bay, Appin. | Tourist site |
| Boat House | X | | SP8609 : Sailing club & heron, Weston Turville Reservoir | |
| Boat Trips | X | | NH5632 : Boat Trips, Loch Ness | Tourist site |
| Boat Yard | X | | TG3724 : Richardsons Boat Yard | |
| Boating Lake | X | | TA0527 : Pickering Park, Hull | Blue lettering |
| Bothy | X | X | NY6734 : Bothy | |
| Boundary Rock | X | | at SX635885 | |
| Boundary Work | X | | SX6771 : Boundary on Holne Moor | |
| Breakwater | X | X | SX4853 : Mount Batten Breakwater | With name on 25K |
| Brewery | X | X | TF4958 : Bateman's Brewery, Wainfleet | |
| Brick Works | X | X | NU0909 : Thrunton Brick Works | |
| Broch | X | X | NC0206 : Broch and ruined cottage, Achlochan | Non-Roman |
| Burial Chamber | X | X | SM7228 : Coetan Arthur burial chamber, St Davids Head | Non-Roman |
| Burial Ground | X | X | NH3407 : Auchteraw Burial Ground | |
| Burial Mound | X | | SO0311 : Enclosure at Cwm Moel | Non-Roman |
| Burnt Mounds | X | X | HU5361 : Burnt Mound | |
| Business Centre | X | | at TQ267342 | |
| Business Park | X | X | SU6555 : Chineham Business Park | |
| Butterfly House | X | X | SK5384 : Butterfly House | Tourist site |
| Butts | X | | TL8182 : Rifle Range, Thetford Forest | Rifle butts, not grouse butts |
| Cairn | X | X | NX4674 : Summit cairn - Drigmorn Hill | |
| Cairn & Cist | | X | SH6311 : Cairn & Cist Above Friog | Non-Roman |
| Cairn Circle & Cist | X | X | SX7478 : Cist burial , Houndtor Down | Non-Roman |
| Cairnfield | X | | at NO827943 | Non-Roman |
| Camp Site | X | | NY6760 : Cell block, Featherstone POW camp | Disused PoW camp |
| Canal | X | | SK4092 : Sheffield to Keadby Canal | Blue lettering |
| Canal Basin | X | | NS7276 : The Forth and Clyde canal at Auchinstarry. | |
| Canal Centre | X | | ST2788 : Fourteen Locks Canal Centre | Tourist site |
| Candle Centre | X | X | SN0736 : Cilgwyn candle centre | Tourist site |
| Canoe Centre | X | | SO5924 : A day on the river | Tourist site |
| Car Compound | X | | TQ5081 : Wind Turbine, Hornchurch Marshes | Photo is a wind turbine in the compound |
| Car Factory | X | X | SK2930 : Toyota Car Factory, Burnaston, Derby | |
| Caravan Site | X | | SP4070 : Hill Top Park Princethorpe | Prefabricated mobile homes not touring caravans |
| Cashel | X | X | NG3768 : Eilean Chaluim Chille | Non-Roman. A cashel is an enclosing wall, usually around a church, and more often seen in Ireland. |
| Castell | X | X | SM9239 : Castell, Pencaer | Non-Roman. Word Castell alone is at SM765279 on 25K |
| Castle | X | X | SV8815 : Cromwell's Castle, Tresco, Scilly | Non-Roman |
| Cathedral | X | | NZ2742 : Late evening light on Durham Cathedral | Here with World Heritage symbol |
| Cattle Grid | X | X | SD9875 : Cattle grid | |
| Cauld | | X | NT4914 : Cauld, Wilton | Weir on 25K. The word Cauld appears near the Scottish border. |
| Causeway | X | X | NU0842 : Refuge on the causeway across Holy Island Sands | Named on 25K, at NU101431 |
| Cave | X | | HU5380 : Sea cave below the Heights of Ramnageo | |
| Celtic Monastery | X | | HY2328 : Brough of Birsay | Non-Roman |
| Chair lift | X | X | NO1377 : The Cairnwell chair lift | |
| Chalk Pit | X | X | TG2404 : The chalk pit by Caistor St Edmund | |
| Chalybeate | X | | SE7299 : Barn, Job's Well (Chalybeate) | In: Job's Well (Chalybeate) |
| Chambered Cairn | X | X | NH5364 : Balnacrae Chambered Cairn | Non-Roman. Chambered Cairn (remains of) on 25K. |
| Chantry | | X | TQ6574 : Milton Chantry | Non-Roman |
| Chapel (rems of) | X | X | TF6741 : Hunstanton - St Edmunds Chapel | Non-Roman. Named on 25K. |
| Chemical Wks | | X | ST5482 : Severnside fertilizer works | |
| China Clay Works | X | | SX5762 : Lee Moor China Clay Works | |
| China Clay Workings | X | | SX1280 : Stone Circle with modern china clay works. | |
| Church (remains of) | X | | TL7280 : Remains of St Peter's Church, Eriswell | Non-Roman |
| Church | X | X | TL2082 : St Andrew's Church Wood Walton | Non-Roman. Named on 25K. |
| Cider Farm | X | X | ST2525 : Tanpits Cider Farm, Taunton | Tourist site |
| Cinema | X | | SP3588 : Odeon Bedworth | |
| Cist | X | | SX6684 : Fernworthy reservoir cist | Non-Roman. Also in Cairn & Cist, Cairn Circle & Cist |
| City Farm | X | | NT2372 : Gorgie City Farm | Tourist site |
| City Hall | X | | TA0928 : Hull City Hall | |
| Civic Centre | | X | TQ2205 : Adur Civic Centre | |
| Clay Pigeon Shooting | X | X | NH9210 : Clay pigeon shooting | Tourist site |
| Clay Pit | X | X | SX8575 : Southacre Quarry Clay Storage Sheds | |
| Clay Works | X | | SX8476 : Newbridge clay works | |
| Cliff Lift | X | X | SZ0890 : Bournemouth: West Cliff Lift | |
| Clinic | X | | NY4353 : Entrance to the Carleton Clinic | |
| Club House | X | | at SV907117 | Most Club Houses have abbreviation CH, this has words |
| Cnoc | X | X | NG4173 : Cnoc Roll | Named as Cnoc Roll |
| Coast Guard Lookout Station | X | | TF5768 : Coast Guard lookout station at Ingoldmells point | |
| Coastal Park | | X | TQ9374 : Barton's point Coastal Park | Tourist site |
| Coastguard Cottages | X | | SZ3084 : Coastguard Cottages near the Needles | On map, but 3 are let out |
| Coastguard House | X | | TA3131 : Coastguard House Seaside Lane Tunstall | |
| Coastwatch Sta | | X | TF5768 : Coast Guard lookout station at Ingoldmells point | |
| College | X | | TL4561 : Cambridge Regional College | |
| Colliery | X | X | SP2690 : Entrance to Daw Mill Colliery | Named on 25K |
| Conduit | X | | SK2686 : Redmires conduit | |
| Construction Yard | | X | NS1853 : Hunterston Construction Yard Basin | |
| Container Terminal | X | X | NS2776 : Container handling machines | Named on 25K |
| Continental Ferry Port | X | | SU6301 : Portsmouth continental ferry port | |
| Control Tower | X | | NL9944 : Airport complex Tiree | |
| Convent | X | X | SO8301 : Poor Clares Convent, Woodchester | |
| Conveyor | | X | TQ5976 : Aerial Conveyor, West Thurrock | No word on 25K |
| Conveyor belts | | X | TA1716 : Looking towards Immingham Ore Terminal | |
| Copper Mines | | X | SH4390 : Flooded copper pits below the summit of Mynydd Parys | Non-Roman |
| Copper Pits | X | | SH4390 : Flooded copper pits below the summit of Mynydd Parys | Non-Roman |
| Country Club | X | X | SP2285 : Forest of Arden Hotel and Country Club | |
| Country Park | X | X | TF6719 : Bawsey Country Park | Named on 25K |
| County Hall | X | X | SX9291 : Clock tower, County Hall, Exeter | |
| Covenanter's Grave | X | X | NT0752 : Covenanter's Cairn towards Ayrshire | Non-Roman on similar NS8462 : Covenanter's grave |
| Covered | X | | at NJ142229 | in "Fergan's Well (covered)" |
| Craft Centre | X | X | SJ1258 : Ruthin Craft Centre | Tourist site |
| Crannog | X | X | NN8637 : Crannog in Loch Freuchie | |
| Crannog (submerged) | X | | NN5811 : Loch Lubnaig | Non-Roman. Photo shows loch. |
| Cricket Ground | | X | SK5838 : Trent Bridge cricket ground | |
| Crofts | X | X | NJ3517 : A Netherton croft | |
| Cross | | X | SX6671 : Horse Ford Cross | Non-Roman |
| Cross | | X | SX6671 : Horse Ford Cross | Non-Roman |
| Cultivation Terraces | X | | SJ6501 : The cultivation terraces of Arlescott village | Non-Roman |
| Cup marked Rock | X | | NM8603 : Cup-marked rock | Non-Roman. Another nearby is shown as Cup marked Stone. |
| Cursus | X | X | SU0014 : Down Farm, Dorset Cursus | Non-Roman |
| Custom House | X | | TQ3380 : Custom House, London | |
| Cycle Hire | X | | SW9274 : Camel Trail cycle hire at Padstow | Tourist site |
| Cycle Route | | X | TA1729 : Early Morning on the old Hull to Withernsea Railway Track | |
| Cycle Trails | | X | SN8586 : Hafren Forest Picnic site | Tourist site, bike symbol on 25K |
| Cycling Centre | X | X | SJ8798 : Manchester Velodrome | Tourist site - as National Cycling Centre on 25K |