SL9 postcode district: Chalfont St Peter and around
SL9 is a postcode district in England, with 872 postcodes in use in 5 sectors. It has postcodes in Chalfont St Peter and Gerrards Cross. It is split between 2 councils: Buckinghamshire (869 postcodes) and Three Rivers (3). 3 of its 872 postcodes are in Hertfordshire. ONS lists no county for the other 869.
- Postcodes in use
- 872
- Sectors
- 5
- Councils
- 2 councils
- Places
- 2 places
Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. See all our data sources
Every postcode in SL9, and which are new since 2020
- New since 2020: 25
- In use before 2020: 847
- Outline: where 5 or more new postcodes since 2020 lie together
Of the 872 postcodes in SL9 that ONS places, 25 are new since 2020 and 847 were in use before 2020.
Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. New since 2020 means it came into use in January 2020 or later. A dashed outline shows where 5 or more lie within 150 metres of each other. It is not a boundary, and no boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode.
The middle of its postcodes: latitude 51.5981, longitude -0.5557. Open this area on OpenStreetMap
Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; when each came into use: the same directory; roads, rivers and built-up areas: Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre. How we use them
The 5 newest postcodes
Where the new postcodes lie together
- 8 new postcodes since 2020, outlined on the map. SL9 0FL, is the newest of them.
What broadband can you get in SL9?
Ofcom reports on 843 of the 872 postcodes in SL9. At 688 of them every home and business can get gigabit broadband.
Ofcom gives each postcode's share of homes and businesses, not how many there are, so these count postcodes. Each postcode page has its own figures. A provider's checker answers for one address.
Check one address on Ofcom's checkerSource: Ofcom, Connected Nations, Spring 2026, data for January 2026, Open Government Licence v3.0. How we use it
Is SL9 at risk of flooding?
28 of the 872 postcodes in SL9 have a home or business in an area at risk of flooding from rivers or the sea, the Environment Agency says. At those, it puts 23 homes and businesses in an area at high or medium risk.
High: 3.3% or more a year (1 in 30). Medium: 1% to 3.3% a year. Low: 0.1% to 1% a year. Very low: under 0.1% a year (1 in 1,000). Each band is the chance of flooding in any one year.
Homes and businesses in an area at risk of flooding from rivers or the sea, as the Environment Agency counts them, added up over the postcodes. It is for the land, not each building, and leaves out surface water, groundwater and sewers. Each postcode page has its own figures and its flood warning areas.
Source: Environment Agency, Risk of Flooding from Rivers and Sea (postcodes in areas at risk), published 6 July 2026, Open Government Licence v3.0. How we use it
What do homes sell for in SL9?
Homes in SL9 sold for a typical £834,650 in the 12 months to August 2026, across 222 sales, down 2.9% on the 12 months before, HM Land Registry's figures show.
- Detached £994,500 118 sales
- Semi-detached £737,500 30 sales
- Terraced £585,000 27 sales
- Flat or maisonette £430,000 47 sales
Each bar is that kind's typical price, against the most expensive kind here.
Standard sales of homes at market value. A typical price is the median, the middle sale. Sales take weeks to be registered, so the last month or two are incomplete. Each postcode page gives the figure for its own postcode sector.
Source: HM Land Registry Price Paid Data, files dated 28 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it
Postcodes in SL9
Pick a sector, then a postcode. A sector is the district plus the next digit.
UK postcode format explainedPlaces in SL9
Towns and villages with postcodes in SL9, and how many each has here.
Who covers SL9
How many of the district's postcodes in use fall under each council, constituency and police force area.
Councils
What council am I in?Constituencies
- Chesham and Amersham843
- Beaconsfield26
- South West Hertfordshire3
Police force areas
- Thames Valley869
- Hertfordshire3
Next to SL9
"Next to" is by number: the districts before and after SL9 in the SL area.
Check a postcode
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